Submission #17470

#	Time	Username	Problem	Language	Result	Execution time	Memory
17470		Namnamseo	Star triangles (IZhO11_triangle)	C++98	100 / 100	251 ms	8116 KiB

triangle

#include <cstdio>
#include <algorithm>

using namespace std;

int cx[300010];
int cy[300010];

int px[300010];
int pxn;
int py[300010];
int pyn;

int n;

int x[300010];
int y[300010];

int main()
{
    scanf("%d",&n);
    int i;
    for(i=0;i<n;++i){
        scanf("%d%d",x+i,y+i);
        px[i]=x[i]; py[i]=y[i];
    }
    sort(px,px+n); sort(py,py+n);
    pxn=unique(px,px+n)-px;
    pyn=unique(py,py+n)-py;
    for(i=0;i<n;++i){
        x[i]=lower_bound(px,px+pxn,x[i])-px;
        y[i]=lower_bound(py,py+pyn,y[i])-py;
        ++cx[x[i]];
        ++cy[y[i]];
    }
    long long ans=0;
    for(i=0;i<n;++i){
        ans += (cx[x[i]]-1)*1ll*(cy[y[i]]-1);
    }
    printf("%lld\n",ans);
    return 0;
}

• Subtask 1: 100 / 100