ural 1272. Non-Yekaterinburg Subway

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题目链接：http://acm.timus.ru/problem.aspx?space=1&num=1272

题意描述：图里现存两种连接方式（通道）：tunnel和bridge，修地铁顾名思义在地下，所以bridge尽量少；那么任务就是用现有的两种通道建立连通图，给出需要的最少的bridge数；

思路就是并查集，先用tunnel合并，再用bridge合并；

AC代码：

#define _CRT_SECURE_NO_WARNINGS#include <iostream>#include <stdio.h>#include <string>#include <algorithm>#include <vector>#include <queue>#include <cmath>#include <map>using namespace std;struct Node{int x, y;};vector<int>parent;int getParent(int num){return num == parent[num] ? num : parent[num] = getParent(parent[num]);}bool link(Node *node){int a = getParent(node->x);int b = getParent(node->y);if (a != b){parent[a] = b;return true;}return false;}void func(){int N, T, B;cin >> N >> T >> B;for (int i = 0; i <= N; i++)parent.push_back(i);Node node;for (int i = 0; i < T; i++){cin >> node.x >> node.y;link(&node);}int ans = 0;for (int i = 0; i < B; i++){cin >> node.x >> node.y;if (link(&node))ans++;}cout << ans << endl;}int main(){freopen("out.txt", "w", stdout);freopen("in.txt", "r", stdin);func();}

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