Submission #335609

#	Time	Username	Problem	Language	Result	Execution time	Memory
335609		StanCatalin	Star triangles (IZhO11_triangle)	C++14	0 / 100	1 ms	364 KiB

triangle

#include <iostream>
#include <algorithm>
#include <fstream>

using namespace std;

ifstream in("triangles.in");
ofstream out("triangles.out");

const int dim = 3e5 + 5;

int n,vec1[dim],vec2[dim],vec3[dim],vec4[dim];
pair<int,int> a[dim];

int main()
{
    in >> n;
    for (int i=1; i<=n; i++)
    {
        in >> a[i].first >> a[i].second;
    }
    sort(a+1,a+n+1);

    for (int i=1; i<=n; i++)
    {
        vec1[a[i].second]++;
        vec4[a[i].first]++;
    }
    for (int i=n; i>=1; i--)
    {
        vec2[a[i].second]++;
        vec3[a[i].first]++;
    }
    int ans = 0;
    for (int i=1; i<=n; i++)
    {
        int x = a[i].first;
        int y = a[i].second;
        ans += (vec4[x] - 1) * (vec1[y] - 1) + (vec4[x] - 1) * (vec3[y] - 1) + (vec2[x] - 1) * (vec3[y] - 1) + (vec2[x] - 1) * (vec1[y] - 1);
    }
    out << ans/4;
    return 0;
}

• Subtask 1: 0 / 100