Submission #27258

#	Time	Username	Problem	Language	Result	Execution time	Memory
27258		TAMREF	Star triangles (IZhO11_triangle)	C++11	100 / 100	269 ms	9052 KiB

triangle

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mx=3e5+5;
int x[mx], y[mx], xc[mx], yc[mx], xo[mx], yo[mx];
int main(){
    int N;
    scanf("%d",&N);
    for(int i=0;i<N;i++){
        scanf("%d%d",&x[i],&y[i]);
        xc[i]=x[i], yc[i]=y[i];
    }
    int u,v;
    sort(xc,xc+N); u=unique(xc,xc+N)-xc;
    sort(yc,yc+N); v=unique(yc,yc+N)-yc;
    for(int i=0;i<N;i++){
        x[i]=lower_bound(xc,xc+u,x[i])-xc;
        ++xo[x[i]];
        y[i]=lower_bound(yc,yc+v,y[i])-yc;
        ++yo[y[i]];
    }
    ll ans=0;
    for(int i=0;i<N;i++){
        ans+=1LL*(xo[x[i]]-1)*(yo[y[i]]-1);
    }
    printf("%lld\n",ans);
}

Compilation message (stderr)

triangle.cpp: In function 'int main()':
triangle.cpp:8:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&N);
                   ^
triangle.cpp:10:34: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&x[i],&y[i]);
                                  ^

• Subtask 1: 100 / 100