//Activity Selection 
#include <bits/stdc++.h>
using namespace std;
 
int main() {
    vector<pair<int,int>> arr = {{1,2},{2,3},{3,4},{1,3}};
 
    sort(arr.begin(), arr.end(), [](auto &a, auto &b){
        return a.second < b.second;
    });
 
    int count = 1;
    int last = arr[0].second;
 
    for (int i = 1; i < arr.size(); i++) {
        if (arr[i].first >= last) {
            count++;
            last = arr[i].second;
        }
    }
 
    cout << "Max non-overlapping intervals: " << count << endl;
}

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