UVA 539 - The Settlers of Catan

题目大意：给你 N 个结点， M 条路， 求一条最长的路，这条路不能经过一个结点两次

解题思路：直接 DFS ，探索所有可能的路，记录下最长的那条

#include <cstdio>int node[30] = {0}, road[30][2], n, m, max, count = 0;int dfs(int num) {bool end = true;for (int i = 0; i < m; i++)if ((road[i][0] == num || road[i][1] == num) && node[i] == 0) { //寻找连接此结点的路end = false; //假如此结点能连接下一个结点则说明此结点不是终点node[i] = 1; //标记此结点已走过count++;dfs(road[i][0] == num ? road[i][1] : road[i][0]); //探索连接了此结点的路的另一端点node[i] = 0;count--;}if (end && count > max)max = count;}int main () {while (scanf("%d%d", &n, &m), n) {max = 0;for (int i = 0; i < m; i++)scanf("%d%d", &road[i][0], &road[i][1]);for (int i = 0; i < n; i++) //从各个结点出发,探索线路dfs(i);printf("%d\n", max);}return 0;}