桶排序

src/main/java/com/dota/bucket/Solution.java

@@ -1,9 +1,67 @@
 package com.dota.bucket;
 
-import java.util.HashMap;
+import java.util.*;
-import java.util.Map;
-
 class Solution {
+	public int[] topKFrequent(int[] nums, int k) {
+		var book = new ArrayList<ArrayList<Integer>>(nums.length+1);
+		var map = new HashMap<Integer, Integer>();
+		int i = 0;
+		for (int num : nums) {
+			map.put(num, map.getOrDefault(num, 0) + 1);
+			book.add(i++, new ArrayList<>());
+		}
+		book.add(new ArrayList<>());
+
+		var res = new int[k];
+		for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
+			book.get(entry.getValue()).add(entry.getKey());
+		}
+
+		i = nums.length;
+		var index = 0;
+		for (;i>=0&&index<k;i--) {
+			if (!book.get(i).isEmpty()) {
+				for(var j = 0;j<book.get(i).size();j++) {
+					res[index++] = book.get(i).get(j);
+				}
+			}
+		}
+
+		return res;
+	}
+}
+
+class Solution3 {
+	public List<String> topKFrequent(String[] words, int k) {
+		Map<String, Integer> map = new HashMap<>();
+		var book = new int[words.length];
+		var res = new ArrayList<String>();
+		for (int i = 0; i < words.length; i++) {
+			if (map.containsKey(words[i])) {
+				book[map.get(words[i])]++;
+			} else {
+				map.put(words[i], i);
+				book[i] = 1;
+			}
+		}
+
+		for (int i = 0; i < k; i++) {
+			var max = 0;
+			for (int j = 0; j < book.length; j++) {
+				if (book[j] > book[max]) {
+					max = j;
+				}else if (book[j] == book[max]) {
+					max = words[j].compareTo(words[max]) > 0 ? max : j;
+				}
+			}
+			book[max] = 0;
+			res.add(words[max]);
+		}
+		return res;
+	}
+}
+
+class Solution2 {
 	public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
 		Map<Long, Long> map = new HashMap<>();
 		for (int i = 0; i < nums.length; i++) {