hdu 2182 哈密頓繞行世界問題 搜尋 dfs

題目連結：here

分析：很簡單一個搜尋。。。直接暴搜即可。。不知道為啥夏天的風把他分類到level1.。。。

代碼：

#include <iostream>#include <cstdio>using namespace std;int ansnum;int neigh[22][3];bool vis[22];int state[22];int m;void dfs(int x, int num){int i, j;if (num == 20){bool flag = false;for (i=0; i<3; i++) if (neigh[x][i] == m) flag = true;if (flag){ansnum ++;printf("%d: ", ansnum);for (j=0; j<20; j++) printf(" %d", state[j]);printf(" %d\n", m);}return ;}for (i=0; i<3; i++){if (!vis[neigh[x][i]]){state[num] = neigh[x][i];vis[neigh[x][i]] = true;dfs(neigh[x][i], num+1);vis[neigh[x][i]] = false;}}}int main(){int i;for (i=1; i<=20; i++){scanf("%d %d %d", &neigh[i][0], &neigh[i][1], &neigh[i][2]);}while (scanf("%d", &m), m){ansnum = 0;memset(vis, false, sizeof(vis));vis[m] = true;state[0] = m;dfs(m, 1);}return 0;}