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| back to board | Why does a simple sort of pairs + finding the median not work? Posted by sweepea  11 Nov 2024 16:21All the test cases I've come up with have been solved correctly by this method but no AC :(
 code:
 ```
 #include <bits/stdc++.h>
 
 using namespace std;
 
 int main() {
 int n;
 cin >> n;
 
 vector<vector<int>> x(n, vector<int>(3, 0));
 
 for (int i = 0; i < n; i++) {
 cin >> x[i][0];
 cin >> x[i][1];
 x[i][2] = i + 1;
 }
 
 sort(x.begin(), x.end());
 
 auto med = (n - 1) / 2;
 
 cout << x[med][2] << " " << x[med + 1][2];
 }
 
 ```
 
 Edited by author 11.11.2024 16:23
 
 Edited by author 11.11.2024 16:23
Re: Why does a simple sort of pairs + finding the median not work? Posted by sweepea  12 Nov 2024 14:43To answer my own question.
 The above code will select for the 2 median points. These don't necessarily create a median line.
 
 Consider the following test case:
 4
 0 10
 1 1
 2 2
 3 10
 
 
 
 The above alogorithm would select (1, 1) and (2,2), which partitions the plane into a section with 2 points, and a section with 0 points; the above approach is incorrect.
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