Ice_cream’s world I
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 10 0 1 1 2 1 3 2 4 3 4 0 5 5 6 6 7 3 6 4 7
Sample Output 3
#include<cstdio> #define K 10011 int st[K],ans=0; int find(int p) { int ch=p; int t; while(p!=st[p]) p=st[p]; while(ch!=p) { t=st[ch]; st[ch]=p; ch=t; } return p; } void node(int x,int y) { int fx=find(x); int fy=find(y); if(fx!=fy) st[fx]=fy; else ans++; } int main() { int N,M,a,b,i; while(scanf("%d%d",&N,&M)!=EOF) { for(i=0;i<=N;i++) st[i]=i; while(M--) { scanf("%d%d",&a,&b); node(a,b); } printf("%d\n",ans); ans=0; } return 0; }