算法1
思路:求和:s[x2][y2]-s[x1-1][y2]-s[x2][y1-1]+s[x1-1][y1-1];
初始化:s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+a[i][j];
妙啊
C++ 代码
#include<iostream>
using namespace std;
int n,m,q;
const int N=1010;
int a[N][N],s[N][N];
int main(){
scanf("%d%d%d",&n,&m,&q);
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
scanf("%d",&a[i][j]);
}
}
for(int i=1;i<=n;i++){
for(int j=1;j<=m;j++){
s[i][j]=s[i-1][j]+s[i][j-1]-s[i-1][j-1]+a[i][j];
}
}
while(q--){
int x1,y1,x2,y2;
scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
// cout<<x1<<y1<<x2<<y2;
printf("%d\n",s[x2][y2]-s[x1-1][y2]-s[x2][y1-1]+s[x1-1][y1-1]);
}
return 0;
}