Merge overlapping intervals.cpp

/**
 * Title     : Merge overlapping intervals
 * Author    : Nitin Tayal
 **/
#include<bits/stdc++.h>
using namespace std;

vector<vector<int>> mergeIntervals(vector<vector<int>>& intervals) {

    if (intervals.size() <= 1)
        return intervals;

    sort(intervals.begin(), intervals.end());

    vector<vector<int> > res;
    res.emplace_back(intervals[0]);

    for (int i = 1; i < intervals.size(); ++i) {

        if (intervals[i][0] <= res.back()[1])
            res.back()[1] = max(res.back()[1], intervals[i][1]);
        else
            res.emplace_back(intervals[i]);
    }

    return res;
}

int main() {

    int n;
    cout << "Enter the number of intervals : ";
    cin >> n;

    vector<vector<int> > intervals(n);

    cout << "Enter start and end value of each interval : ";
    for (int i = 0; i < n; ++i) {
        int start, end;
        cin >> start >> end;
        intervals[i].emplace_back(start);
        intervals[i].emplace_back(end);
    }

    vector<vector<int> > res = mergeIntervals(intervals);

    cout << "Merged intervals are : ";
    for (int i = 0; i < res.size(); ++i) {
        cout << res[i][0] << ' ' << res[i][1] << '\n';
    }

    return 0;
}