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