杭电 2120 ice cream‘s word

Problem Description

ice_cream's world is a rich country, it has many fertile lands. Today, the queen of ice_cream wants award land to diligent ACMers. So there are some watchtowers are set up, and wall between watchtowers be build, in order to partition the ice_cream’s world. But how many ACMers at most can be awarded by the queen is a big problem. One wall-surrounded land must be given to only one ACMer and no walls are crossed, if you can help the queen solve this problem, you will be get a land.

 

Input

In the case, first two integers N, M (N<=1000, M<=10000) is represent the number of watchtower and the number of wall. The watchtower numbered from 0 to N-1. Next following M lines, every line contain two integers A, B mean between A and B has a wall(A and B are distinct). Terminate by end of file.

 

Output

Output the maximum number of ACMers who will be awarded.
One answer one line.

 

Sample Input

8 100 11 21 32 43 40 55 66 73 64 7

 

Sample Output

3
 
 
#include<stdio.h>int per[10001];int flag;int find(int x){int r=x;while(r!=per[r]){r=per[r];}return r;}int mix(int x,int y){int fx=find(x);int fy=find(y);if(fx!=fy){per[fy]=fx;}else flag++;}int main(){int m,n,x,y;while(~scanf("%d%d",&n,&m)){flag=0;for(int i=0;i<n;i++){per[i]=i;}while(m--){scanf("%d%d",&x,&y);    mix(x,y);}printf("%d\n",flag);}return 0;}