HDOJ 4607 - Park Visit

来源：互联网发布：js锚点定位滚动导航编辑：程序博客网时间：2024/04/28 13:26

用树形DP找到这颗树距离最远的两个点....对于一个询问K..若小于最远距离..显然只要走最远的这条边走K-1个边就行了..

当K大于了最远距离..就要去走其他的点...而去其他点必须再回到这个主线..所以要加上(最远距离上点总数-K)*2...

Program:

#include<iostream>#include<stack>#include<queue>#include<stdio.h>#include<algorithm>#include<string.h>#include<cmath>#define ll long long#define oo 1000000007#define MAXN 100010using namespace std;vector<int> Tree[MAXN];int dis[MAXN],M;void dfs(int x,int f){      int i,m=Tree[x].size();      dis[x]=1;      for (i=0;i<m;i++)        if (Tree[x][i]!=f)        {               dfs(Tree[x][i],x);               M=max(M,dis[x]+dis[Tree[x][i]]);               dis[x]=max(dis[x],dis[Tree[x][i]]+1);                       }      return;}int main(){         int T,i,n,k;       scanf("%d",&T);      while (~scanf("%d%d",&n,&k))      {             for (i=1;i<=n;i++) Tree[i].clear();             for (i=1;i<n;i++)             {                    int x,y;                    scanf("%d%d",&x,&y);                    Tree[x].push_back(y);                    Tree[y].push_back(x);             }             memset(dis,0,sizeof(dis));             M=0;             dfs(1,0);             while (k--)             {                    int x;                    scanf("%d",&x);                    if (x<=M) printf("%d\n",x-1);                         else printf("%d\n",M-1+(x-M)*2);              }      }      return 0;}