bzoj 1218: [HNOI2003]激光炸弹

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cstring>
 4 #include<cstdlib>
 5 #include<cmath>
 6 #include<queue>
 7 #include<algorithm>
 8 #include<vector>
 9 #define M 5009
10 #define EPS 1e-10
11 #define MO 10000
12 #define ll long long
13 using namespace std;
14 ll read()
15 {
16     char ch=getchar();
17     ll x=0,f=1;
18     for(;ch<‘0‘||ch>‘9‘;ch=getchar())
19         if(ch==‘-‘)
20           f=-1;
21     for(;ch>=‘0‘&&ch<=‘9‘;ch=getchar())
22         x=x*10+ch-‘0‘;
23     return x*f;
24 }
25 int n,sum[M][M],r,x[M],y[M];
26 int main()
27 {
28    n=read();
29    r=read();
30    for(int i=1;i<=n;i++)
31      {
32        x[i]=read()+1;
33        y[i]=read()+1;
34        sum[x[i]][y[i]]+=read();
35      }
36    for(int i=1;i<=5001;i++)
37      for(int j=1;j<=5001;j++)
38        sum[i][j]+=sum[i-1][j]+sum[i][j-1]-sum[i-1][j-1];
39    r--;
40    int mx=0;
41    for(int i=1;i<=5001-r;i++)
42      for(int j=1;j<=5001-r;j++)
43        mx=max(mx,sum[i+r][j+r]-sum[i-1][j+r]-sum[i+r][j-1]+sum[i-1][j-1]);
44    printf("%d\n",mx);
45    return 0;
46 }