POJ 2421 Constructing Roads

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题目链接：
[kuangbin带你飞]专题六最小生成树 D - Constructing Roads

输入矩阵，求最小生成树。其中有的边已经联通，不需要再计算，将其权值置为0即可。

//#include"stdafx.h"#include <iostream>#include <cstdio>#include <cmath>#include<cstring>#include <algorithm>using namespace std;struct edge{    int s, e, w;};edge e[10008];int p[108];int n, ans = 0, cnt = 0;int map[108][108];bool cmp(edge a, edge b) { return a.w < b.w; }int find(int x){ return x == p[x] ? x : p[x] = find(p[x]); }void kruscal(){    sort(e, e + cnt, cmp);    for (int i = 0; i < cnt; i++)    {        int x = find(e[i].s);        int y = find(e[i].e);        if (x != y)        {            p[x] = y;            ans += e[i].w;        }    }    cout << ans << endl;}int main(){    cin >> n;    for (int i = 0; i < n; i++)        for (int j = 0; j < n; j++) cin >> map[i][j];    int m, x, y;    for (int i = 0; i <= n; i++) p[i] = i;    cin >> m;    for (int i = 0; i < m; i++)    {        cin >> x >> y;        //ans += map[x - 1][y - 1];        map[x - 1][y - 1] = 0;    }    for (int i = 0; i < n - 1; i++)        for (int j = i + 1; j < n; j++)            {                e[cnt].s = i;                e[cnt].e = j;                e[cnt++].w = map[i][j];            }    kruscal();    return 0;}

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