Maximum Population Year

You are given a 2D integer array logs where each logs[i] = [birthi, deathi] indicates the birth and death years of the ith person.

The population of some year x is the number of people alive during that year? The ith a person is counted in the year x's population if x is in the inclusive range [birthi, deathi - 1]. Note that the person is not counted in the year that they die.

Return the earliest year with the maximum population.

Example 1:

Input: logs = [[1993,1999],[2000,2010]]
Output: 1993
Explanation: The maximum population is 1, and 1993 is the earliest year with this population.

Example 2:

Input: logs = [[1950,1961],[1960,1971],[1970,1981]]
Output: 1960
Explanation: 
The maximum population is 2, and it had happened in years 1960 and 1970.
The earlier year between them is 1960.

Approach

Java

import java.util.HashMap;

public class MaxPopulationYear {
    public static void main(String[] args) {

        int[][] logs = { { 1993, 1999 }, { 2000, 2010 } };

        System.out.println(maximumPopulation(logs));

    }

    static int maximumPopulation(int[][] logs) {
        HashMap<Integer, Integer> mp = new HashMap<Integer, Integer>();
        for (int[] i : logs) {
            mp.put(i[0] - 1950, mp.getOrDefault(i[0] - 1950, 0) + 1);
            mp.put(i[1] - 1950, mp.getOrDefault(i[1] - 1950, 0) - 1);

        }
        int ans = 0, count = 0, year = 0;

        for (int key : mp.keySet()) {
            count += mp.get(key);
            if (ans < count) {
                ans = count;
                year = key;
            }
        }
        return year + 1950;
    }

}

C++

#include <bits/stdc++.h>
using namespace std;

int maximumPopulation(vector<vector<int>> &logs)
{
    map<int, int> mp;
    for (auto i : logs)
    {
        mp[i[0] - 1950]++;
        mp[i[1] - 1950]--;
    }
    int ans = 0, count = 0, year;
    for (auto i : mp)
    {
        count += i.second;
        if (ans < count)
        {
            ans = count;
            year = i.first;
        }
    }
    return year + 1950;
}

int main()
{
    vector<vector<int>> logs = {{1993, 1999}, {2000, 2010}};

    cout << maximumPopulation(logs) << "\n";

    return 0;
}