Poj 2421 constructing roanalyticdb

Minimum Spanning Tree problem.

Kruskal. merge if an edge already exists.

Find the minimum value. No pitfalls.

G ++ AC.

#include<cstdio>#include<cstring>#include<queue>#include<algorithm>#include<queue>#include<map>#include<stack>#include<iostream>#include<list>#include<set>#include<cmath>#define INF 0x7fffffff#define eps 1e-6using namespace std;int n,m;int fa[101];int father(int x){    if(x!=fa[x])        return fa[x]=father(fa[x]);}struct lx{    int u,v,len;}l[101*101];bool cmp(lx a,lx b){    return a.len<b.len;}int main(){    while(scanf("%d",&n)!=EOF)    {        for(int i=1;i<=n;i++)            fa[i]=i;        int cot=0;        for(int i=1;i<=n;i++)        {            for(int j=1;j<=n;j++)            {                int len;                scanf("%d",&len);                if(i==j)continue;                l[cot].u=i;                l[cot].v=j;                l[cot++].len=len;            }        }        sort(l,l+cot,cmp);        scanf("%d",&m);        while(m--)        {            int u,v;            scanf("%d%d",&u,&v);            u=father(u);            v=father(v);            if(u==v)continue;            fa[v]=u;        }        int ans=0;        for(int i=0;i<cot;i++)        {            int u=father(l[i].u);            int v=father(l[i].v);            if(u==v)continue;            fa[v]=u;            ans+=l[i].len;        }        printf("%d\n",ans);    }}