# Leetcode 1854. Maximum Population Year

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[easy][contest]

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` person is counted in 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: 1993Explanation: 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: 1960Explanation: The maximum population is 2, and it had happened in years 1960 and 1970.The earlier year between them is 1960.`

Constraints:

• `1 <= logs.length <= 100`
• `1950 <= birthi < deathi <= 2050`

[Gary- Java- Hashmap]

Think:

1. use hashmap to count all the exist year
2. if there is an early year have the same population count, update the year