UVA 167 The Sultan’s Successors

题目大意：类八皇后问题，每个格子都有权值
解题思路：回溯

#include <stdio.h>
#include <iostream>
#include <string.h>
using namespace std;
int num[9][9];
int ju[3][20];
int s;
int p;
void dfs(int a) {
    if(a == 8) {
        if(p > s)
            s = p;
        return;
    }
    for(int i = 0; i < 8; i++) {
        if(!ju[0][i] && !ju[1][i+a] && !ju[2][i-a+7]) {
            p = p + num[a][i];
            ju[2][i-a+7] = 1;
            ju[0][i] = 1;
            ju[1][i+a] = 1;
            dfs(a+1);
            p = p - num[a][i];
            ju[2][i-a+7] = 0;
            ju[0][i] = 0;
            ju[1][i+a] = 0;
        }
    }
}
int main() {
    int n;
    cin >> n;
    while(n--) {
        memset(ju, 0, sizeof(ju));
        for(int i = 0; i < 8; i++)
            for(int j = 0; j < 8; j++) {
                cin >> num[i][j];
            }
        s = 0;
        p = 0;
        dfs(0);
        printf("%5d\n", s);
    }
    return 0;
}