POJ 3107 Godfather (树的重心)

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题目地址：POJ 3107
还是裸的树的重心，只不过这个要求将所有的重心都输出。很简单。
代码如下：

#include <iostream>#include <string.h>#include <math.h>#include <queue>#include <algorithm>#include <stdlib.h>#include <map>#include <set>#include <stdio.h>#include <time.h>using namespace std;#define LL __int64#define pi acos(-1.0)//#pragma comment(linker, "/STACK:1024000000")#define root 1, n, 1#define lson l, mid, rt<<1#define rson mid+1, r, rt<<1|1const int mod=1e9+7;const int INF=0x3f3f3f3f;const double eqs=1e-9;const int MAXN=50000+10;struct node {        int v, next;} edge[MAXN<<1];int head[MAXN], cnt, min1, n, num;int sum[MAXN], ans[MAXN];void add(int u, int v){        edge[cnt].v=v;        edge[cnt].next=head[u];        head[u]=cnt++;}void init(){        memset(head,-1,sizeof(head));        cnt=0;        min1=INF;}void dfs(int u, int fa){        int max1=0, i, tot=0;        sum[u]=1;        for(i=head[u]; i!=-1; i=edge[i].next) {                int v=edge[i].v;                if(v==fa) continue ;                dfs(v,u);                sum[u]+=sum[v];                max1=max(max1,sum[v]);                tot+=sum[v];        }        max1=max(max1,n-tot-1);        if(min1>max1) {                min1=max1;                num=0;                ans[num++]=u;        }        else if(min1==max1) {                ans[num++]=u;        }}int main(){        int u, v, i;        while(scanf("%d",&n)!=EOF) {                init();                for(i=1; i<n; i++) {                        scanf("%d%d",&u,&v);                        add(u,v);                        add(v,u);                }                dfs(1,-1);                sort(ans,ans+num);                for(i=0; i<num; i++) {                        printf("%d",ans[i]);                        if(i!=num-1) printf(" ");                        else puts("");                }        }        return 0;}

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