hdoj1102_Constructing Roads（最小生成树）

来源：互联网发布：php zrem 编辑：程序博客网时间：2024/04/30 11:52

用最小生成树kruskal算法求最小建造长度

#include<string.h>#include<iostream>#include<vector>#include<queue>#include<algorithm>using namespace std;struct edge{    int b, e, len;};struct cmpe{    bool operator()(edge e1, edge e2)    {        return e1.len > e2.len;    }};priority_queue<edge, vector<edge>, cmpe> q;int par[200];int find(int x){    int tx = x;    while (par[tx] >= 0)        tx = par[tx];    while (x != tx)    {        int nx = par[x];        par[x] = tx;        x = nx;    }    return tx;}void uni(int x, int y){    if (par[x] == par[y])    {        par[x]--;        par[y] = x;    }    else if (par[x] < par[y])        par[y] = x;    else        par[x] = y;}int kruskal(int n){    int res = 0;    for (int i = 0; i < n-1;)    {        edge te = q.top();        q.pop();        int pb = find(te.b);        int pe = find(te.e);        if (pb != pe)        {            uni(pb, pe);            i++;            res += te.len;        }    }    return res;}int main(){    int n;    while (cin >> n)    {        while (!q.empty())            q.pop();        for (int i = 0; i < n; i++)            for (int j = 0; j < n; j++)            {                int clen;                cin >> clen;                q.push(edge{i,j,clen});            }        int Q;        cin >> Q;        memset(par, -1, sizeof(par));        for (int i = 0; i < Q; i++)        {            int b, e;            cin >> b >> e;            int pb = find(b-1);            int pe = find(e-1);            if (pb != pe)            {                uni(pb, pe);                n--;            }        }        cout << kruskal(n) << endl;    }    return 0;}

0 0