HDU4607+BFS

 /*
 bfs+求树的直径
 关键：if k<=maxs+1 直接输出k-1；
     else： k肯定的是包括最长路。先从最长路的起点出发，再走分支，最后到达最长路的终点。
             因此是2*(k-(maxs+1))+maxs;
 */
 #include<stdio.h>
 #include<string.h>
 #include<stdlib.h>
 #include<algorithm>
 #include<iostream>
 #include<queue>
 #include<map>
 #include<math.h>
 using namespace std;
 typedef long long ll;
 //typedef __int64 int64;
 const int maxn = ;
 const int inf = 0x7fffffff;
 const double pi=acos(-1.0);
 const double eps = 1e-;
 struct Node{
     int v,next;
 }edge[ maxn<< ];
 int cnt,head[ maxn ];
 int vis[ maxn ],dis[ maxn ];
 int maxs,maxNode;
 void init(){
     cnt = ;
     memset( head,-,sizeof( head ) );
 }
 void addedge( int a,int b ){
     edge[ cnt ].v = b;
     edge[ cnt ].next = head[ a ];
     head[ a ] = cnt++;
 
     edge[ cnt ].v = a;
     edge[ cnt ].next = head[ b ];
     head[ b ] = cnt++;
 }
 void bfs( int s,int n ){
     memset( vis,,sizeof( vis ) );
     vis[ s ] = ;
     queue<int>q;
     q.push( s );
     //for( int i=0;i<=n;i++ )
         //dis[ i ] = inf;
     dis[ s ] = ;
     maxs = ;
     while( !q.empty() ){
         int cur = q.front();
         q.pop();
         if( dis[ cur ]>maxs ){
             maxs = dis[ cur ];
             maxNode = cur;
         }
         //maxs = max( maxs,dis[ cur ] );
         for( int i=head[ cur ];i!=-;i=edge[ i ].next ){
             int v = edge[ i ].v;
             if( vis[ v ]== ) continue;
             vis[ v ] = ;
             dis[ v ] = dis[ cur ]+;
             q.push( v );
         }
     }
     return ;
 }
 int main(){
     int T;
     scanf("%d",&T);
     while( T-- ){
         int n,m;
         scanf("%d%d",&n,&m);
         int a,b;
         init();
         int N = n-;
         while( N-- ){
             scanf("%d%d",&a,&b);
             addedge( a,b );
         }
         bfs( ,n );
         bfs( maxNode,n );
         //maxs=the R of the tree
         while( m-- ){
             scanf("%d",&b);
             if( b<=maxs+ ) printf("%d\n",b-);
             else printf("%d\n",*(b-maxs-)+maxs);
         }
     }
     return ;
 }