Submission #1771912

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define N 1116
#define M 1111116

int n,m,x[M],y[M],h[N][N],ans;

int read(){
	int x=0,f=1;char ch=getchar();
	for (;!isdigit(ch);ch=getchar()) if (ch=='-') f=-f;
	for (;isdigit(ch);ch=getchar()) x=x*10+ch-'0';
	return x*f;
}

int main(){
	n=read();m=read();
	for (int i=1;i<=m;i++) x[i]=read(),y[i]=read();
	for (int i=1;i<=n;i++){
		h[i][i]=1;
		for (int j=m;j>=1;j--){
			if (!h[i][x[j]]&&!h[i][y[j]]) continue;
			if (h[i][x[j]]&&h[i][y[j]]) {fill(h[i]+1,h[i]+n+1,1);break;}
			h[i][x[j]]=h[i][y[j]]=1;
		}
	}
	for (int i=1;i<=n;i++)
		for (int j=i+1;j<=n;j++)
			for (int k=1;k<=n;k++)
				if (h[i][k]&&h[j][k])
				{ans++;break;};
	printf("%d\n",n*(n-1)/2-ans);
	return 0;
}

Submission Info

Judge Result