UVA 10269 Adventure of Super Mario 最短路

//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<sstream>
#include<cmath>
#include<climits>
#include<string>
#include<map>
#include<queue>
#include<vector>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define pb(a) push(a)
#define INF 0x1f1f1f1f
#define lson idx<<1,l,mid
#define rson idx<<1|1,mid+1,r
#define PI  3.1415926535898
template<class T> T min(const T& a,const T& b,const T& c) {
    return min(min(a,b),min(a,c));
}
template<class T> T max(const T& a,const T& b,const T& c) {
    return max(max(a,b),max(a,c));
}
void debug() {
#ifdef ONLINE_JUDGE
#else

    freopen("in.txt","r",stdin);
    //freopen("d:\\out1.txt","w",stdout);
#endif
}
int getch() {
    int ch;
    while((ch=getchar())!=EOF) {
        if(ch!=‘ ‘&&ch!=‘\n‘)return ch;
    }
    return EOF;
}


const int maxn=500005;
int n,k,A,B;
struct HeapNode
{
    int d,u;
    bool operator < (const HeapNode &ant) const
    {
        return d>ant.d;
    }
};
struct Edge
{
    int from,to;
    int dist;
};
struct Dijksta
{
    int n;
    set<int> g[maxn];
    int done[maxn];
    int d[maxn];

    void init(int n)
    {
        this->n=n;
        for(int i=0;i<=n;i++)
            g[i].clear();
    }

    void add(int u,int v,int w)
    {
        g[u].insert(v);
    }

    void solve(int s)
    {
        for(int i=0;i<=n;i++)
            d[i]=max(A,B);
        memset(done,0,sizeof(done));
        d[s]=0;
        priority_queue<HeapNode> q;
        q.push((HeapNode){0,s});
        while(!q.empty())
        {
            HeapNode x=q.top();q.pop();
            if(done[x.u])continue;
            int u=x.u;
            done[u]=1;
            for(int v=1;v<=n;v++)if(v!=u)
            {
                int w;
                if(g[u].find(v)!=g[u].end())
                {
                    w=A;
                }else w=B;
                if(w+d[u]<d[v])
                {
                    d[v]=w+d[u];
                    q.push((HeapNode){d[v],v});
                }
            }
        }
    }
};

Dijksta solver;

int main()
{
    while(scanf("%d%d%d%d",&n,&k,&A,&B)!=EOF)
    {
        solver.init(n);
        for(int i=1;i<=k;i++)
        {
            int u,v;scanf("%d%d",&u,&v);
            solver.add(u,v,A);
            solver.add(v,u,A);
        }
        solver.solve(1);
        printf("%d\n",solver.d[n]);
    }
    return 0;
}