bzoj3391

来源：互联网发布：sql注入绕过安全狗编辑：程序博客网时间：2024/05/01 06:57

直接看子树是否大于mx就行了。

#include<cstdio>#include<algorithm>#include<cstring>#include<cmath>#include<queue>#define fo(i,a,b) for(int i=a;i<=b;i++)#define fd(i,a,b) for(int i=a;i>=b;i--)using namespace std;int n,m;const int N=1e5+5;int head[N],next[N],go[N],mx;int tot=0;inline void add(int x,int y){    go[++tot]=y;    next[tot]=head[x];    head[x]=tot;}int vis[N],siz[N],ans[N];inline void dfs(int x){    vis[x]=1;    int i=head[x];    siz[x]=1;    while (i)    {        int v=go[i];        if (!vis[v])        {            dfs(v);            siz[x]+=siz[v];            if (siz[v]>mx)ans[x]=0;        }        i=next[i];    }    if (n-siz[x]>mx)ans[x]=0;}int main(){    scanf("%d",&n);    mx=n>>1;    memset(ans,-1,sizeof(ans));    fo(i,1,n-1)    {        int x,y;        scanf("%d%d",&x,&y);        add(x,y);        add(y,x);    }    dfs(1);    bool bz=0;    fo(i,1,n)    if (ans[i]!=0)    {        printf("%d\n",i);        bz=1;    }    if (!bz)printf("NONE\n");    return 0;}

0 0