PAT T1013 Image Segmentation

krustral算法加并查集，按题给要求维护并查集~

#include<bits/stdc++.h>
using namespace std;
const int maxn=;
const int inf=1e9;
int N,M,x,y;
int c,w;
struct edge {
    int u;
    int v;
    int w;
}Edge[maxn*];
int mst[maxn];
int num[maxn];
int father[maxn];
bool cmp (edge a,edge b) {
    return a.w<b.w;
}
int findfather (int x) {
    int a=x;
    while (x!=father[x]) x=father[x];
    while (a!=father[a]) {
        int z=a;
        a=father[a];
        father[z]=x;
    }
    return x;
}
vector<int> g[maxn];
int main () {
    scanf ("%d %d %d",&N,&M,&c);
    for (int i=;i<N;i++) father[i]=i,num[i]=;
    for (int i=;i<M;i++) {
        scanf ("%d %d %d",&Edge[i].u,&Edge[i].v,&Edge[i].w);
    }
    sort (Edge,Edge+M,cmp);
    for (int i=;i<M;i++) {
        int u=Edge[i].u;
        int v=Edge[i].v;
        int faU=findfather(u);
        int faV=findfather(v);
        if (faU==faV) continue;
        if ((Edge[i].w<=mst[faU]+c/num[faU])&&(Edge[i].w<=mst[faV]+c/num[faV])) {
            if (faU<faV) swap (faU,faV);
            father[faU]=faV;
            if (Edge[i].w>mst[faV]) mst[faV]=Edge[i].w;
            num[faV]+=num[faU];
        }
    }
    for (int i=;i<N;i++)
    g[findfather(i)].push_back(i);
    for (int i=;i<N;i++) {
        if (g[i].size()==) continue;
        sort (g[i].begin(),g[i].end());
        for (int j=;j<g[i].size();j++) {
            if (j!=) printf (" ");
            printf ("%d",g[i][j]);
        }
        printf ("\n");
    }
    return ;
}