Submission #19139

#	Time	Username	Problem	Language	Result	Execution time	Memory
19139		eaststar	Star triangles (IZhO11_triangle)	C++14	100 / 100	535 ms	8936 KiB

triangle

#include <stdio.h>
#include <map>
using namespace std;
#define SZ 300010
map<int,int> a,b;
int x[SZ],y[SZ],xcnt[SZ],ycnt[SZ],s,t;
long long ans;
int main(){
    int i,n;
    scanf("%d",&n);
    for(i=1;i<=n;++i){
        scanf("%d%d",x+i,y+i);
        if(!a[x[i]])a[x[i]]=++s;
        ++xcnt[a[x[i]]];
        if(!b[y[i]])b[y[i]]=++t;
        ++ycnt[b[y[i]]];
    }
    for(i=1;i<=n;++i)ans+=(long long)(xcnt[a[x[i]]]-1)*(ycnt[b[y[i]]]-1);
    printf("%lld",ans);
    return 0;
}

• Subtask 1: 100 / 100