POJ 2492 A Bug's Life（扩展并查集）

#pragma warning(disable:4996)#include <iostream>#include <cstdio>#include <cstring>#include <string>using namespace std;//扩展并查集int fa[2001], relation[2001];//同性为0，异性为1int find(int x){if (x == fa[x])return x;int tmp = fa[x];fa[x] = find(tmp);relation[x] = (relation[x] + relation[tmp]) % 2;return fa[x];}void merge(int x, int y){int fx = find(x);int fy = find(y);if (fx == fy)return;fa[fx] = fy;relation[fx] = (relation[x] + relation[y] == 1) ? 0 : 1;}int main(){int t;scanf("%d", &t);for (int kase = 1; kase <= t; kase++){memset(relation, 0, sizeof relation);for (int i = 1; i < 2001; i++)fa[i] = i;string ans = "";int n, m;scanf("%d %d", &n, &m);for (int i = 1; i <= m; i++){int x, y;scanf("%d %d", &x, &y);if (find(x) == find(y)){if (relation[x] == relation[y])ans = "Suspicious bugs found!";}else{merge(x, y);}}if (ans.size() > 0){cout << "Scenario #" << kase << ':' << endl << ans << endl << endl;}else{cout << "Scenario #" << kase << ':' << endl << "No suspicious bugs found!" << endl << endl;}}return 0;}