蓝桥杯国赛白给记

A310电脑就离谱，明年去北京再战吧

持续更新ing

最后一道填空题：

hp DFS

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#include<bits/stdc++.h> using namespace std; int N; bool vis[6][6]; int ans = 0; int dir[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}}; bool check() {     for(int i = 1; i <= N; ++i) {         for(int j = 1; j <= N; ++j) {             if(!vis[i][j]) {                 return 0;             }         }     }     return 1; } void DFS(int x, int y) {     //cout << x << " " << y << endl;     if(x <= 0 || y <= 0 || x > N || y > N) {         return;     }     if(check()) {         ans++;         return;     }     for(int i = 0; i < 4; ++i) {         int xx = x + dir[i][0];         int yy = y + dir[i][1];         if(!vis[xx][yy]) {             vis[xx][yy] = 1;             DFS(xx, yy);             vis[xx][yy] = 0;                    }     } } int main () {     while(cin >> N) {         ans = 0;         memset(vis, 0, sizeof vis);         for(int i = 1; i <= N; ++i) {             for(int j = 1; j <= N; ++j) {                 memset(vis, 0, sizeof vis);                 vis[i][j] = 1;                 DFS(i, j);             }         }         cout << ans << endl;            } }

 经验：用notepad配环境或者用命令行直接编译运行（g++ sbA310.cpp -> a.exe）死循环ctrl c终止