LeetCode-in-Java
1854. Maximum Population Year
Easy
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 <= 1001950 <= birthi < deathi <= 2050
Solution
public class Solution {
public int maximumPopulation(int[][] logs) {
int[] arr = new int[101];
for (int[] log : logs) {
arr[log[0] - 1950]++;
arr[log[1] - 1950]--;
}
for (int i = 1; i < 101; i++) {
arr[i] += arr[i - 1];
}
int maxyear = 1950;
int max = 0;
for (int i = 0; i < 101; i++) {
if (arr[i] > max) {
max = arr[i];
maxyear = i + 1950;
}
}
return maxyear;
}
}