zoj 3161 Damn Couples

zoj 3161 Damn Couples

#include <stdio.h>#include <cstring>#include <algorithm>using namespace std;int n,m;bool a[510];int f[510];int main(){while(scanf("%d%d",&n,&m)!=EOF){memset(a, 0, sizeof(a));for (int i=0; i<m;i++){int x,y;scanf("%d%d",&x,&y);if (x>y) swap(x,y);if (y!=x+1) continue;a[x]=1;}int ans=n;for (int i=0; i<n; i++)if (a[i]){int j=i;while(j<n&&a[j]) j++;ans-=(j-i+1-(j-i+3)/3);i=j;}printf("%dn",ans);}return 0;}