Leetcode 原题.

这里 N 最大会取到 13, TLE 了

 

代码

#include 
     
      #include 
      
       using namespace std;bool chess[15][15];int n;int cnt;void dfs(int depth) {    if(depth == n) {        cnt ++;        return;    }    for(int i = 0; i < n; i ++) {        bool qualify = true;        for(int j = depth-1; j >= 0; j --) {            if(chess[j][i]) {                qualify = false;                break;            }        }        if(!qualify)            continue;        for(int k = 1; depth-k >= 0 && i-k >= 0; k++) {            if(chess[depth-k][i-k]) {                qualify = false;                break;            }        }        if(!qualify)            continue;        for(int k = 1; depth-k >= 0 && i+k < n; k ++) {            if(chess[depth-k][i+k]) {                qualify = false;                break;            }        }        if(!qualify) {            continue;        }        // qualified        chess[depth][i] = true;        dfs(depth + 1);        chess[depth][i] = false;    }}int main() {    while(scanf("%d", &n) != EOF) {        cnt = 0;        dfs(0);        cout << cnt << endl;    }    return 0;}