为了得到书法大家的真传，小E同学下定决心去拜访住在魔法森林中的隐士。魔法森林可以被看成一个包含个N节点M条边的无向图，节点标号为1..N，边标号为1..M。初始时小E同学在号节点1，隐士则住在号节点N。小E需要通过这一片魔法森林，才能够拜访到隐士。
魔法森林中居住了一些妖怪。每当有人经过一条边的时候，这条边上的妖怪就会对其发起攻击。幸运的是，在号节点住着两种守护精灵：A型守护精灵与B型守护精灵。小E可以借助它们的力量，达到自己的目的。
只要小E带上足够多的守护精灵，妖怪们就不会发起攻击了。具体来说，无向图中的每一条边Ei包含两个权值Ai与Bi。若身上携带的A型守护精灵个数不少于Ai，且B型守护精灵个数不少于Bi，这条边上的妖怪就不会对通过这条边的人发起攻击。当且仅当通过这片魔法森林的过程中没有任意一条边的妖怪向小E发起攻击，他才能成功找到隐士。
由于携带守护精灵是一件非常麻烦的事，小E想要知道，要能够成功拜访到隐士，最少需要携带守护精灵的总个数。守护精灵的总个数为A型守护精灵的个数与B型守护精灵的个数之和。
第1行包含两个整数N,M，表示无向图共有N个节点，M条边。 接下来M行，第行包含4个正整数Xi,Yi,Ai,Bi，描述第i条无向边。其中Xi与Yi为该边两个端点的标号，Ai与Bi的含义如题所述。 注意数据中可能包含重边与自环。
输出一行一个整数：如果小E可以成功拜访到隐士，输出小E最少需要携带的守护精灵的总个数；如果无论如何小E都无法拜访到隐士，输出“-1”（不含引号）。
2<=n<=50,000
0<=m<=100,000
1<=ai ,bi<=50,000
题解：
卡时真是一件痛苦的事儿。。考场上肯定卡不出来。。。
考场上怎么就sb的去枚举a，二分b，在spfa呢？更直观的想法不就是枚举a做mst吗？脑袋短路了。。。
正解是LCT，蒟蒻不会，先spfa水过。。
枚举a，做spfa即可，但这样只有30分，考虑各种优化：
1.每次枚举的时候 d 数组不用清空，如果 d[n]值发生了变化，一定走了一条当前枚举的 a 的上限，则每次用 d [n]+xx 来更新答案，如果没发生变化，也不会影响答案，因为xx是递增的
2.如果这样直接做的话会是答案错误，这是为什么？
这是因为在加入了一条新边之后，不一定能更新从 1 出发的点，所以其他点就不会被加入队列，这条边就没用被用到！
所以我们应当在枚举到一条边的时候，将这条边的两端打标记，spfa从这些有标记的点出发即可
3.发现TLE。。。
如果打印出ans的变化值可以发现，在开始很长时间内ans都是 inf，也就是说 1 与 n 都不连通
这样我们可以从小到大加入边，用并查集维护连通性，直到 1 与 n 第一次连通时，我们开始做 spfa，这样可以省掉一些无用的过程
综合以上3点，终于AC。。。
代码：
1.考场35分（真是RP啊。。。）
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d1,d2,head,fa:array[0..maxn] of longint; 6 q:array[0..10*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,ll,tot,rr,x,y,point,mid:longint; 10 ans,n,m:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 procedure sort1(l,r:longint); 21 var i,j,x,y:longint; 22 begin 23 i:=l;j:=r;x:=a[(i+j)>>1]; 24 repeat 25 while a[i]>x do inc(i); 26 while a[j]<x do dec(j); 27 if i<=j then 28 begin 29 y:=a[i];a[i]:=a[j];a[j]:=y; 30 inc(i);dec(j); 31 end; 32 until i>j; 33 if i<r then sort1(i,r); 34 if j>l then sort1(l,j); 35 end; 36 procedure sort2(l,r:longint); 37 var i,j,x,y:longint; 38 begin 39 i:=l;j:=r;x:=b[(i+j)>>1]; 40 repeat 41 while b[i]<x do inc(i); 42 while b[j]>x do dec(j); 43 if i<=j then 44 begin 45 y:=b[i];b[i]:=b[j];b[j]:=y; 46 inc(i);dec(j); 47 end; 48 until i>j; 49 if i<r then sort2(i,r); 50 if j>l then sort2(l,j); 51 end; 52 procedure insert(x,y,z,w:longint); 53 begin 54 inc(tot); 55 with e[tot] do 56 begin 57 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 58 end; 59 end; 60 procedure spfa; 61 var i,x,y,h,t,tmp1,tmp2:longint; 62 begin 63 for i:=1 to n do d1[i]:=inf; 64 for i:=1 to n do d2[i]:=inf; 65 fillchar(v,sizeof(v),false); 66 h:=0;t:=1;q[1]:=1;d1[1]:=0;d2[1]:=0; 67 while h<t do 68 begin 69 inc(h); 70 x:=q[h];v[x]:=false; 71 i:=head[x]; 72 while i<>0 do 73 begin 74 y:=e[i].go; 75 tmp1:=max(d1[x],e[i].v1); 76 tmp2:=max(d2[x],e[i].v2); 77 if (tmp1<=xx) and (tmp2<=yy) and (tmp2<d2[y]) then 78 begin 79 d1[y]:=tmp1;d2[y]:=tmp2; 80 if not(v[y]) then 81 begin 82 v[y]:=true; 83 inc(t);q[t]:=y; 84 end; 85 end; 86 i:=e[i].next; 87 end; 88 end; 89 end; 90 procedure init; 91 begin 92 readln(n,m); 93 for i:=1 to n do fa[i]:=i; 94 for i:=1 to m do 95 begin 96 readln(x,y,a[i],b[i]); 97 xx:=find(x);yy:=find(y); 98 if xx<>yy then fa[xx]:=yy; 99 insert(x,y,a[i],b[i]);insert(y,x,a[i],b[i]); 100 end; 101 sort1(1,m); 102 sort2(1,m); 103 end; 104 procedure work1; 105 begin 106 xx:=a[1];point:=1; 107 while true do 108 begin 109 ll:=1;rr:=m; 110 while ll<rr do 111 begin 112 mid:=(ll+rr)>>1; 113 yy:=b[mid]; 114 spfa; 115 if d2[n]<>inf then rr:=mid else ll:=mid+1; 116 end; 117 inc(point); 118 while (point<=m) and (d1[n]<a[point]) do inc(point); 119 if point>m then break; 120 xx:=a[point]; 121 if d1[n]+d2[n]<ans then ans:=d1[n]+d2[n]; 122 end; 123 writeln(ans); 124 end; 125 procedure work2; 126 begin 127 for i:=1 to 100 do 128 begin 129 xx:=random(a[1])+1; 130 yy:=random(b[m])+1; 131 spfa; 132 if d1[n]+d2[n]<ans then ans:=d1[n]+d2[n]; 133 end; 134 writeln(ans); 135 end; 136 begin 137 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 138 reset(input);rewrite(output); 139 init; 140 ans:=inf; 141 if find(1)<>find(n) then writeln(‘-1‘) else if n*m*16<50000000 then work1 else work2; 142 close(input);close(output); 143 end.
2.朴素SPFA55分
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d1,d2,head,fa:array[0..maxn] of longint; 6 q:array[0..10*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,l,tot,r,x,y:longint; 10 ans,n,m:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 function min(x,y:longint):longint; 21 begin 22 if x<y then exit(x) else exit(y); 23 end; 24 25 procedure sort(l,r:longint); 26 var i,j,x,y:longint; 27 begin 28 i:=l;j:=r;x:=a[(i+j)>>1]; 29 repeat 30 while a[i]<x do inc(i); 31 while a[j]>x do dec(j); 32 if i<=j then 33 begin 34 y:=a[i];a[i]:=a[j];a[j]:=y; 35 inc(i);dec(j); 36 end; 37 until i>j; 38 if i<r then sort(i,r); 39 if j>l then sort(l,j); 40 end; 41 procedure insert(x,y,z,w:longint); 42 begin 43 inc(tot); 44 with e[tot] do 45 begin 46 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 47 end; 48 end; 49 procedure spfa; 50 var i,x,y,h,t,tmp1,tmp2:longint; 51 begin 52 for i:=1 to n do d1[i]:=inf; 53 for i:=1 to n do d2[i]:=inf; 54 fillchar(v,sizeof(v),false); 55 h:=0;t:=1;q[1]:=1;d1[1]:=0;d2[1]:=0; 56 while h<t do 57 begin 58 inc(h); 59 x:=q[h];v[x]:=false; 60 i:=head[x]; 61 while i<>0 do 62 begin 63 y:=e[i].go; 64 tmp1:=max(d1[x],e[i].v1); 65 tmp2:=max(d2[x],e[i].v2); 66 if (tmp1<=xx) and (tmp2<d2[y]) then 67 begin 68 d1[y]:=tmp1;d2[y]:=tmp2; 69 if not(v[y]) then 70 begin 71 v[y]:=true; 72 inc(t);q[t]:=y; 73 end; 74 end; 75 i:=e[i].next; 76 end; 77 end; 78 end; 79 procedure init; 80 begin 81 readln(n,m); 82 for i:=1 to n do fa[i]:=i; 83 for i:=1 to m do 84 begin 85 readln(x,y,a[i],b[i]); 86 xx:=find(x);yy:=find(y); 87 if xx<>yy then fa[xx]:=yy; 88 insert(x,y,a[i],b[i]);insert(y,x,a[i],b[i]); 89 end; 90 sort(1,m); 91 end; 92 procedure work1; 93 begin 94 xx:=a[1];l:=0;r:=m; 95 while true do 96 begin 97 while a[l]=a[l-1] do inc(l); 98 inc(l);xx:=a[l]; 99 if l>r then break; 100 spfa; 101 while d1[n]+d2[n]<=a[r] do dec(r); 102 ans:=min(ans,d1[n]+d2[n]); 103 xx:=a[r]; 104 spfa; 105 ans:=min(ans,d1[n]+d2[n]); 106 while d1[n]<=a[r] do dec(r); 107 end; 108 writeln(ans); 109 end; 110 begin 111 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 112 reset(input);rewrite(output); 113 init; 114 ans:=inf; 115 if find(1)<>find(n) then writeln(‘-1‘) else work1; 116 close(input);close(output); 117 end.
3.MST40分
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 arr=array[0..maxn] of longint; 6 var a,b,c,d,head,fa,aa:arr; 7 e:array[0..maxn*2] of node; 8 v,hash:array[0..maxn] of boolean; 9 i,j,xx,yy,l,tot,r,x,y,cnt:longint; 10 ans,n,m:int64; 11 flag:boolean; 12 function find(x:longint):longint; 13 begin 14 if fa[x]<>x then fa[x]:=find(fa[x]); 15 exit(fa[x]); 16 end; 17 function max(x,y:longint):longint; 18 begin 19 if x>y then exit(x) else exit(y); 20 end; 21 function min(x,y:longint):longint; 22 begin 23 if x<y then exit(x) else exit(y); 24 end; 25 procedure swap(var x,y:longint); 26 var t:longint; 27 begin 28 t:=x;x:=y;y:=t; 29 end; 30 31 procedure sort(l,r:longint); 32 var i,j,x:longint; 33 begin 34 i:=l;j:=r;x:=aa[(i+j)>>1]; 35 repeat 36 while aa[i]<x do inc(i); 37 while aa[j]>x do dec(j); 38 if i<=j then 39 begin 40 swap(aa[i],aa[j]); 41 inc(i);dec(j); 42 end; 43 until i>j; 44 if i<r then sort(i,r); 45 if j>l then sort(l,j); 46 end; 47 procedure sort1(l,r:longint); 48 var i,j,x:longint; 49 begin 50 i:=l;j:=r;x:=b[(i+j)>>1]; 51 repeat 52 while b[i]<x do inc(i); 53 while b[j]>x do dec(j); 54 if i<=j then 55 begin 56 swap(a[i],a[j]);swap(b[i],b[j]);swap(c[i],c[j]);swap(d[i],d[j]); 57 inc(i);dec(j); 58 end; 59 until i>j; 60 if i<r then sort1(i,r); 61 if j>l then sort1(l,j); 62 end; 63 procedure insert(x,y,z,w:longint); 64 begin 65 inc(tot); 66 with e[tot] do 67 begin 68 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 69 end; 70 end; 71 procedure init; 72 begin 73 readln(n,m); 74 for i:=1 to n do fa[i]:=i; 75 for i:=1 to m do 76 begin 77 readln(x,y,a[i],b[i]); 78 xx:=find(x);yy:=find(y); 79 if xx<>yy then fa[xx]:=yy; 80 c[i]:=x;d[i]:=y; 81 end; 82 aa:=a; 83 sort(1,m);sort1(1,m); 84 end; 85 procedure dfs(x,t1,t2:longint); 86 var i,y:longint; 87 begin 88 v[x]:=true; 89 if x=n then begin flag:=true;ans:=min(ans,t1+t2);exit;end; 90 i:=head[x]; 91 while i<>0 do 92 begin 93 y:=e[i].go; 94 if not(v[y]) then dfs(y,max(t1,e[i].v1),max(t2,e[i].v2)); 95 if flag then break; 96 i:=e[i].next; 97 end; 98 end; 99 procedure mst; 100 var i,j:longint; 101 begin 102 fillchar(v,sizeof(v),false); 103 fillchar(head,sizeof(head),0);tot:=0; 104 for i:=1 to n do fa[i]:=i; 105 j:=1; 106 for i:=1 to n-1 do 107 begin 108 while (j<=m) and ((a[j]>xx) or (find(d[j])=find(c[j])))do inc(j); 109 if j>m then exit; 110 fa[find(d[j])]:=find(c[j]); 111 insert(c[j],d[j],a[j],b[j]);insert(d[j],c[j],a[j],b[j]); 112 end; 113 //for i:=1 to n do writeln(head[i]); 114 flag:=false; 115 dfs(1,0,0); 116 end; 117 procedure work1; 118 begin 119 //for i:=1 to m do write(aa[i],‘ ‘);writeln; 120 l:=0;r:=m; 121 while true do 122 begin 123 inc(l); 124 while aa[l]=aa[l-1] do inc(l);//writeln(l,‘ ‘,aa[l],‘ ‘,r); 125 inc(cnt); 126 if l>r then break; 127 xx:=aa[l]; 128 mst; 129 while ans<=aa[r] do dec(r); 130 inc(cnt); 131 xx:=aa[r]; 132 mst; 133 dec(r);while aa[r]=aa[r+1] do dec(r); 134 end; 135 writeln(ans); 136 end; 137 procedure work2; 138 begin 139 fillchar(hash,sizeof(hash),false); 140 for i:=1 to 200 do 141 begin 142 repeat 143 x:=random(m)+1; 144 until not(hash[aa[x]]); 145 xx:=aa[x]; 146 mst; 147 end; 148 writeln(ans); 149 end; 150 151 begin 152 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 153 reset(input);rewrite(output); 154 randomize; 155 init; 156 ans:=inf; 157 if find(1)<>find(n) then writeln(‘-1‘) 158 else if n*m<20000000 then work1 else work2; 159 close(input);close(output); 160 end.
4.SPFA优化80分
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d,c1,c2,head,fa:array[0..maxn] of longint; 6 q:array[0..10*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,l,z,w,tot,r,x,y:longint; 10 ans,n,m,mm:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 function min(x,y:longint):longint; 21 begin 22 if x<y then exit(x) else exit(y); 23 end; 24 procedure swap(var x,y:longint); 25 var t:longint; 26 begin 27 t:=x;x:=y;y:=t; 28 end; 29 30 procedure sort(l,r:longint); 31 var i,j,x:longint; 32 begin 33 i:=l;j:=r;x:=a[(i+j)>>1]; 34 repeat 35 while a[i]<x do inc(i); 36 while a[j]>x do dec(j); 37 if i<=j then 38 begin 39 swap(a[i],a[j]);swap(b[i],b[j]);swap(c1[i],c1[j]);swap(c2[i],c2[j]); 40 inc(i);dec(j); 41 end; 42 until i>j; 43 if i<r then sort(i,r); 44 if j>l then sort(l,j); 45 end; 46 procedure insert(x,y,z,w:longint); 47 begin 48 inc(tot); 49 with e[tot] do 50 begin 51 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 52 end; 53 end; 54 procedure spfa; 55 var i,x,y,h,t,tmp:longint; 56 begin 57 h:=0;t:=0; 58 for i:=1 to n do if v[i] then begin inc(t);q[t]:=i;end; 59 //for i:=1 to t do writeln(q[i]); 60 while h<t do 61 begin 62 inc(h); 63 x:=q[h];v[x]:=false; 64 i:=head[x]; 65 while i<>0 do 66 begin 67 y:=e[i].go; 68 tmp:=max(d[x],e[i].v2); 69 //writeln(e[i].v1,‘ ‘,xx,‘ ‘,tmp,‘ ‘,d[y]); 70 if (e[i].v1<=xx) and (tmp<d[y]) then 71 begin 72 d[y]:=tmp;//writeln(d[y]); 73 if not(v[y]) then 74 begin 75 v[y]:=true; 76 inc(t);q[t]:=y; 77 end; 78 end; 79 i:=e[i].next; 80 end; 81 end; 82 end; 83 procedure init; 84 begin 85 readln(n,m);mm:=m;m:=0; 86 for i:=1 to n do fa[i]:=i; 87 for i:=1 to mm do 88 begin 89 readln(x,y,z,w); 90 xx:=find(x);yy:=find(y); 91 if xx<>yy then fa[xx]:=yy; 92 if x=y then continue; 93 inc(m);c1[m]:=x;c2[m]:=y;a[m]:=z;b[m]:=w; 94 insert(x,y,z,w);insert(y,x,z,w); 95 end; 96 sort(1,m); 97 // for i:=1 to m do writeln(c1[i],‘ ‘,c2[i],‘ ‘,a[i],‘ ‘,b[i]); 98 end; 99 procedure main; 100 begin 101 d[1]:=0; 102 for i:=2 to n do d[i]:=inf; 103 //for i:=1 to n do writeln(i,‘ ‘,d[i],‘ ‘,head[i]); 104 l:=1;r:=m; 105 while true do 106 begin 107 fillchar(v,sizeof(v),false); 108 while a[l]=a[l+1] do 109 begin 110 v[c1[l]]:=true;v[c2[l]]:=true; 111 inc(l); 112 end; 113 v[c1[l]]:=true;v[c2[l]]:=true; 114 xx:=a[l]; //writeln(xx); 115 if l>r then break; 116 spfa; 117 //for i:=1 to n do writeln(i,‘ ‘,d[i]); 118 //if d[n]+xx=19923 then writeln(c1[l],‘ ‘,c2[l],‘ ‘,a[l],‘ ‘,b[l]); 119 //writeln(d[n],‘ ‘,xx); 120 ans:=min(ans,d[n]+xx);// writeln(d[n],‘ ‘,l,‘ ‘,r,‘ ‘,xx); 121 while ans<=a[r] do dec(r); 122 inc(l); 123 end; 124 writeln(ans); 125 end; 126 begin 127 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 128 reset(input);rewrite(output); 129 init; 130 ans:=inf<<1; 131 if find(1)<>find(n) then writeln(‘-1‘) else main; 132 close(input);close(output); 133 end.
5.SPFA再优化75分。。。
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d,c1,c2,head,fa:array[0..maxn] of longint; 6 q:array[0..10*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,l,z,w,tot,r,x,y:longint; 10 ans,n,m,mm:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 function min(x,y:longint):longint; 21 begin 22 if x<y then exit(x) else exit(y); 23 end; 24 procedure swap(var x,y:longint); 25 var t:longint; 26 begin 27 t:=x;x:=y;y:=t; 28 end; 29 30 procedure sort(l,r:longint); 31 var i,j,x:longint; 32 begin 33 i:=l;j:=r;x:=a[(i+j)>>1]; 34 repeat 35 while a[i]<x do inc(i); 36 while a[j]>x do dec(j); 37 if i<=j then 38 begin 39 swap(a[i],a[j]);swap(b[i],b[j]);swap(c1[i],c1[j]);swap(c2[i],c2[j]); 40 inc(i);dec(j); 41 end; 42 until i>j; 43 if i<r then sort(i,r); 44 if j>l then sort(l,j); 45 end; 46 procedure insert(x,y,z,w:longint); 47 begin 48 inc(tot); 49 with e[tot] do 50 begin 51 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 52 end; 53 end; 54 procedure spfa; 55 var i,x,y,h,t,tmp:longint; 56 begin 57 h:=0;t:=0; 58 for i:=1 to n do if v[i] then begin inc(t);q[t]:=i;end; 59 //for i:=1 to t do writeln(q[i]); 60 while h<t do 61 begin 62 inc(h); 63 x:=q[h];v[x]:=false; 64 i:=head[x]; 65 while i<>0 do 66 begin 67 y:=e[i].go; 68 tmp:=max(d[x],e[i].v2); 69 //writeln(e[i].v1,‘ ‘,xx,‘ ‘,tmp,‘ ‘,d[y]); 70 if (e[i].v1<=xx) and (tmp<d[y]) then 71 begin 72 d[y]:=tmp;//writeln(d[y]); 73 if not(v[y]) then 74 begin 75 v[y]:=true; 76 inc(t);q[t]:=y; 77 end; 78 end; 79 i:=e[i].next; 80 end; 81 end; 82 end; 83 procedure init; 84 begin 85 readln(n,m);mm:=m;m:=0; 86 for i:=1 to n do fa[i]:=i; 87 for i:=1 to mm do 88 begin 89 readln(x,y,z,w); 90 xx:=find(x);yy:=find(y); 91 if xx<>yy then fa[xx]:=yy; 92 //if x=y then continue; 93 inc(m);c1[m]:=x;c2[m]:=y;a[m]:=z;b[m]:=w; 94 insert(x,y,z,w);insert(y,x,z,w); 95 end; 96 sort(1,m); 97 // for i:=1 to m do writeln(c1[i],‘ ‘,c2[i],‘ ‘,a[i],‘ ‘,b[i]); 98 end; 99 procedure main; 100 begin 101 d[1]:=0; 102 for i:=2 to n do d[i]:=inf; 103 //for i:=1 to n do writeln(i,‘ ‘,d[i],‘ ‘,head[i]); 104 l:=1;r:=m; 105 for i:=1 to n do fa[i]:=i; 106 while find(1)<>find(n) do begin fa[find(c1[l])]:=find(c2[l]);inc(l);end; 107 //writeln(l,‘ ‘,find(1),‘ ‘,find(n)); 108 while a[l]=a[l-1] do inc(l); 109 v[1]:=true;xx:=a[l-1];spfa;ans:=min(ans,d[n]+xx); 110 while true do 111 begin 112 fillchar(v,sizeof(v),false); 113 while a[l]=a[l+1] do 114 begin 115 v[c1[l]]:=true;v[c2[l]]:=true; 116 inc(l); 117 end; 118 v[c1[l]]:=true;v[c2[l]]:=true; 119 xx:=a[l]; //writeln(xx); 120 if l>r then break; 121 spfa; 122 //for i:=1 to n do writeln(i,‘ ‘,d[i]); 123 //if d[n]+xx=19923 then writeln(c1[l],‘ ‘,c2[l],‘ ‘,a[l],‘ ‘,b[l]); 124 //writeln(d[n],‘ ‘,xx); 125 ans:=min(ans,d[n]+xx);// writeln(d[n],‘ ‘,l,‘ ‘,r,‘ ‘,xx); 126 while ans<=a[r] do dec(r); 127 inc(l); 128 end; 129 writeln(ans); 130 end; 131 begin 132 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 133 reset(input);rewrite(output); 134 init; 135 ans:=inf<<1; 136 if find(1)<>find(n) then writeln(‘-1‘) else main; 137 close(input);close(output); 138 end.
6.原来发现数组开小了。。。100分，苦逼的调试
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d,c1,c2,head,fa:array[0..maxn] of longint; 6 q:array[0..100*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,l,z,w,tot,r,x,y:longint; 10 ans,n,m,mm:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 function min(x,y:longint):longint; 21 begin 22 if x<y then exit(x) else exit(y); 23 end; 24 procedure swap(var x,y:longint); 25 var t:longint; 26 begin 27 t:=x;x:=y;y:=t; 28 end; 29 30 procedure sort(l,r:longint); 31 var i,j,x:longint; 32 begin 33 i:=l;j:=r;x:=a[(i+j)>>1]; 34 repeat 35 while a[i]<x do inc(i); 36 while a[j]>x do dec(j); 37 if i<=j then 38 begin 39 swap(a[i],a[j]);swap(b[i],b[j]);swap(c1[i],c1[j]);swap(c2[i],c2[j]); 40 inc(i);dec(j); 41 end; 42 until i>j; 43 if i<r then sort(i,r); 44 if j>l then sort(l,j); 45 end; 46 procedure insert(x,y,z,w:longint); 47 begin 48 inc(tot); 49 with e[tot] do 50 begin 51 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 52 end; 53 end; 54 procedure spfa; 55 var i,x,y,h,t,tmp:longint; 56 begin 57 //writeln(1); 58 h:=0;t:=0; 59 for i:=1 to n do if v[i] then begin inc(t);q[t]:=i;end; 60 //for i:=1 to t do writeln(q[i]); 61 while h<t do 62 begin 63 inc(h); 64 x:=q[h];v[x]:=false; //writeln(x); 65 i:=head[x]; 66 while i<>0 do 67 begin 68 y:=e[i].go; 69 tmp:=max(d[x],e[i].v2); 70 //writeln(e[i].v1,‘ ‘,xx,‘ ‘,tmp,‘ ‘,d[y]); 71 if (e[i].v1<=xx) and (tmp<d[y]) then 72 begin 73 d[y]:=tmp;//writeln(d[y]); 74 if not(v[y]) then 75 begin 76 v[y]:=true; 77 inc(t);q[t]:=y; 78 end; 79 end; 80 i:=e[i].next; 81 end; 82 end; 83 end; 84 procedure init; 85 begin 86 readln(n,m);mm:=m;m:=0; 87 for i:=1 to n do fa[i]:=i; 88 for i:=1 to mm do 89 begin 90 readln(x,y,z,w); 91 xx:=find(x);yy:=find(y); 92 if xx<>yy then fa[xx]:=yy; 93 if x=y then continue; 94 inc(m);c1[m]:=x;c2[m]:=y;a[m]:=z;b[m]:=w; 95 insert(x,y,z,w);insert(y,x,z,w); 96 end; 97 sort(1,m);//writeln(m); 98 //for i:=1 to m do writeln(i,‘ ‘,c1[i],‘ ‘,c2[i],‘ ‘,a[i],‘ ‘,b[i]); 99 end; 100 procedure main; 101 begin 102 d[1]:=0; 103 for i:=2 to n do d[i]:=inf; 104 //for i:=1 to n do writeln(i,‘ ‘,d[i],‘ ‘,head[i]); 105 l:=1;r:=m; 106 for i:=1 to n do fa[i]:=i; 107 while find(1)<>find(n) do 108 begin 109 //writeln(l,‘ ‘,find(1),‘ ‘,find(n)); 110 //writeln(c1[l],‘ ‘,c2[l]); 111 xx:=find(c1[l]);yy:=find(c2[l]); 112 if xx<>yy then fa[xx]:=yy; 113 inc(l); 114 end; 115 //writeln(l,‘ ‘,find(1),‘ ‘,find(n)); 116 while a[l]=a[l-1] do inc(l);//writeln(l); 117 v[1]:=true;xx:=a[l-1];//writeln(xx); 118 spfa; 119 //for i:=1 to n do writeln(i,‘ ‘,d[i]); 120 ans:=min(ans,d[n]+xx);//writeln(‘ ‘,ans); 121 while true do 122 begin 123 //writeln(‘ ‘,ans); 124 fillchar(v,sizeof(v),false); 125 if l>r then break; 126 while a[l]=a[l+1] do 127 begin 128 v[c1[l]]:=true;v[c2[l]]:=true; 129 inc(l); 130 end; 131 v[c1[l]]:=true;v[c2[l]]:=true; 132 xx:=a[l]; //writeln(xx); 133 if l>r then break; 134 spfa; 135 //for i:=1 to n do writeln(i,‘ ‘,d[i]); 136 //if d[n]+xx=19923 then writeln(c1[l],‘ ‘,c2[l],‘ ‘,a[l],‘ ‘,b[l]); 137 //writeln(d[n],‘ ‘,xx); 138 ans:=min(ans,d[n]+xx);//writeln(d[n],‘ ‘,l,‘ ‘,r,‘ ‘,xx); 139 while ans<=a[r] do dec(r); 140 inc(l); 141 end; 142 writeln(ans); 143 end; 144 begin 145 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 146 reset(input);rewrite(output); 147 init; 148 ans:=inf<<1; 149 if find(1)<>find(n) then writeln(‘-1‘) else main; 150 close(input);close(output); 151 end.
7.去掉调试更清晰。。。
1 const inf=maxlongint>>2;maxn=100000+10; 2 type node=record 3 from,go,next,v1,v2:longint; 4 end; 5 var a,b,d,c1,c2,head,fa:array[0..maxn] of longint; 6 q:array[0..100*maxn] of longint; 7 e:array[0..maxn*2] of node; 8 v:array[0..maxn] of boolean; 9 i,j,xx,yy,l,z,w,tot,r,x,y:longint; 10 ans,n,m,mm:int64; 11 function find(x:longint):longint; 12 begin 13 if fa[x]<>x then fa[x]:=find(fa[x]); 14 exit(fa[x]); 15 end; 16 function max(x,y:longint):longint; 17 begin 18 if x>y then exit(x) else exit(y); 19 end; 20 function min(x,y:longint):longint; 21 begin 22 if x<y then exit(x) else exit(y); 23 end; 24 procedure swap(var x,y:longint); 25 var t:longint; 26 begin 27 t:=x;x:=y;y:=t; 28 end; 29 30 procedure sort(l,r:longint); 31 var i,j,x:longint; 32 begin 33 i:=l;j:=r;x:=a[(i+j)>>1]; 34 repeat 35 while a[i]<x do inc(i); 36 while a[j]>x do dec(j); 37 if i<=j then 38 begin 39 swap(a[i],a[j]);swap(b[i],b[j]);swap(c1[i],c1[j]);swap(c2[i],c2[j]); 40 inc(i);dec(j); 41 end; 42 until i>j; 43 if i<r then sort(i,r); 44 if j>l then sort(l,j); 45 end; 46 procedure insert(x,y,z,w:longint); 47 begin 48 inc(tot); 49 with e[tot] do 50 begin 51 from:=x;go:=y;next:=head[x];head[x]:=tot;v1:=z;v2:=w; 52 end; 53 end; 54 procedure spfa; 55 var i,x,y,h,t,tmp:longint; 56 begin 57 h:=0;t:=0; 58 for i:=1 to n do if v[i] then begin inc(t);q[t]:=i;end; 59 while h<t do 60 begin 61 inc(h); 62 x:=q[h];v[x]:=false; 63 i:=head[x]; 64 while i<>0 do 65 begin 66 y:=e[i].go; 67 tmp:=max(d[x],e[i].v2); 68 if (e[i].v1<=xx) and (tmp<d[y]) then 69 begin 70 d[y]:=tmp; 71 if not(v[y]) then 72 begin 73 v[y]:=true; 74 inc(t);q[t]:=y; 75 end; 76 end; 77 i:=e[i].next; 78 end; 79 end; 80 end; 81 procedure init; 82 begin 83 readln(n,m);mm:=m;m:=0; 84 for i:=1 to n do fa[i]:=i; 85 for i:=1 to mm do 86 begin 87 readln(x,y,z,w); 88 xx:=find(x);yy:=find(y); 89 if xx<>yy then fa[xx]:=yy; 90 if x=y then continue; 91 inc(m);c1[m]:=x;c2[m]:=y;a[m]:=z;b[m]:=w; 92 insert(x,y,z,w);insert(y,x,z,w); 93 end; 94 sort(1,m); 95 96 end; 97 procedure main; 98 begin 99 d[1]:=0; 100 for i:=2 to n do d[i]:=inf; 101 l:=1;r:=m; 102 for i:=1 to n do fa[i]:=i; 103 while find(1)<>find(n) do 104 begin 105 xx:=find(c1[l]);yy:=find(c2[l]); 106 if xx<>yy then fa[xx]:=yy; 107 inc(l); 108 end; 109 while a[l]=a[l-1] do inc(l); 110 v[1]:=true;xx:=a[l-1]; 111 spfa; 112 ans:=min(ans,d[n]+xx); 113 while true do 114 begin 115 fillchar(v,sizeof(v),false); 116 if l>r then break; 117 while a[l]=a[l+1] do 118 begin 119 v[c1[l]]:=true;v[c2[l]]:=true; 120 inc(l); 121 end; 122 v[c1[l]]:=true;v[c2[l]]:=true; 123 xx:=a[l]; 124 if l>r then break; 125 spfa; 126 ans:=min(ans,d[n]+xx); 127 while ans<=a[r] do dec(r); 128 inc(l); 129 end; 130 writeln(ans); 131 end; 132 begin 133 assign(input,‘forest.in‘);assign(output,‘forest.out‘); 134 reset(input);rewrite(output); 135 init; 136 ans:=inf<<1; 137 if find(1)<>find(n) then writeln(‘-1‘) else main; 138 close(input);close(output); 139 end.
原文：http://www.cnblogs.com/zyfzyf/p/3888025.html
