# Leetcode 1854. Maximum Population Year

1 min readMay 9, 2021

[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:** 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.

**Constraints:**

`1 <= logs.length <= 100`

`1950 <= birthi < deathi <= 2050`

**[Gary- Java- Hashmap]**

Think:

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