HDU 1856 More is better

题目链接~~>

做题感悟:这题是并查集按个数合并的运用。

解题思路:只要将父亲节点存整个树的节点数,并且每次更新最大值就可以了(ps: n==0 时输出 1)。具体讲解见:

代码:

#include<stdio.h>
#include<iostream>
#include<map>
#include<stack>
#include<string>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std ;
#define LEN sizeof(struct node)
const double PI = 3.1415926 ;
const double INF = 99999999 ;
const int MX =10000005 ;
int father[MX] ;
int find(int x) // 路径压缩
{
    return  father[x] < 0 ? x : father[x]=find(father[x]) ;
}
int main()
{
    int n ;
    while(~scanf("%d",&n))
    {
       for(int i=1 ;i<=10000000 ;i++)
           father[i]=-1 ;
       int best=-1,ax,ay,x,y ;
       for(int i=0 ;i<n ;i++)
       {
           scanf("%d%d",&x,&y) ;
           ax=find(x) ;
           ay=find(y) ;
           if(ax!=ay)
           {
               if(father[ax]<father[ay])
               {
                   father[ax]+=father[ay] ;
                   father[ay]=ax ;
                   best = father[ax] < best ? father[ax] : best ;
               }
               else
               {
                   father[ay]+=father[ax] ;
                   father[ax]=ay ;
                   best = father[ay] < best ? father[ay] : best ;
               }
           }
       }
       printf("%d\n",-best) ;
    }
    return 0 ;
}


 

 

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