add 1854

fishercoder1534 · fishercoder1534 · commit d48f7dbff710 · 2021-05-09T08:29:22.000-07:00
diff --git a/README.md b/README.md
@@ -8,6 +8,7 @@ _If you like this project, please leave me a star._ &#9733;
 
 |  #  |      Title     |   Solutions   | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|--------|-------------|-------------
+|1854|[Maximum Population Year](https://leetcode.com/problems/maximum-population-year/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1854.java) ||Easy|Array|
 |1848|[Minimum Distance to the Target Element](https://leetcode.com/problems/minimum-distance-to-the-target-element/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1848.java) ||Easy|Array|
 |1845|[Seat Reservation Manager](https://leetcode.com/problems/seat-reservation-manager/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1845.java) ||Medium|Heap, Design|
 |1844|[Replace All Digits with Characters](https://leetcode.com/problems/replace-all-digits-with-characters/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1844.java) ||Easy|String|
diff --git a/src/main/java/com/fishercoder/solutions/_1854.java b/src/main/java/com/fishercoder/solutions/_1854.java
@@ -0,0 +1,25 @@
+package com.fishercoder.solutions;
+
+import java.util.TreeMap;
+
+public class _1854 {
+    public static class Solution1 {
+        public int maximumPopulation(int[][] logs) {
+            TreeMap<Integer, Integer> map = new TreeMap<>();
+            for (int[] log : logs) {
+                for (int start = log[0]; start < log[1]; start++) {
+                    map.put(start, map.getOrDefault(start, 0) + 1);
+                }
+            }
+            int maxPop = 0;
+            int maxPopYear = 0;
+            for (int year : map.keySet()) {
+                if (map.get(year) > maxPop) {
+                    maxPop = map.get(year);
+                    maxPopYear = year;
+                }
+            }
+            return maxPopYear;
+        }
+    }
+}
