Arrays Exported

Author: YuqiZ2020

0-Arrays/Arrays.md

@@ -315,6 +315,11 @@ class Solution {
 
 ---
 
+### [136.](136-Single-Number/136-Single-Number.java) Simgle Number
+**<font color=#C8A1E6> Sort; HashMap </font>**
+
+---
+
 ### [169.](169-Majority-Element/169-Majority-Element-Sort.java) Majority Element
 **<font color=#C8A1E6> Sort; HashMap </font>**
 
@@ -357,7 +362,17 @@ _时间复杂度：O(n)； 空间复杂度：O(n)_
 ---
 
 ### 1481. Least Number of Unique Integers after K Removals
+**<font color=#C8A1E6> Sort; HashMap; Greedy </font>**
+
+#### [解法一](1481-Least-Number-of-Unique-Integers-after-K-Removals/1481-Least-Number-of-Unique-Integers-after-K-Removals.cpp)：Bucket Sort从较低出现频率的数字开始去除
+
+因为需要最后Unique的Number最少，所以可以从出现频率最低的数字开始一个一个去除，直到不能再去除位置。可以用HashMap来保存每个数字出现的频率，再把所有频率排序（用C++的Map自动排序），然后从频率低到高一个一个减少数字，最后看还剩多少特殊的数字即可。
+
+#### [解法二](1481-Least-Number-of-Unique-Integers-after-K-Removals/1481-Least-Number-of-Unique-Integers-after-K-Removals.java)：直接排序
+
+[参考](https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals/discuss/686376/Simple-C%2B%2B-O(N-log-N)-VIDEO-SOL)
 
+直接在记录频率的过程中把某出现频率对应的数字存进一个数组中，将数组排序，最后从低到高进行处理即可。
 
 ## <font color=#7F71D9>其他：</font>
 ### 9. Palindrome Number 
@@ -373,4 +388,4 @@ _时间复杂度：O(n)； 空间复杂度：O(n)_
 **<font color=#C8A1E6> HashMap </font>**
 ### 1464. Maximum Product of Two Elements in an Array
 ### 1470. Shuffle the Array
-### 5453. Running Sum of 1d Array    
+### 1480. Running Sum of 1d Array    

0-Arrays/Arrays.pdf

@@ -4,13 +4,13 @@ Notes, Codes and Ideas on LeetCode Problems
 
 ## Arrays 
 
-- [x] Two Pointers: 26, 27, 88, 283, 905, 941, 986, 1089， 1471
+- [x] Two Pointers: 21, 26, 27, 88, 283, 905, 941, 986, 1089, 1471
 
 - [x] 简单遍历: 1, 448, 1299
 
-- [x] Sort: 75, 169, 973, 977, 1051, 1465
+- [x] Sort: 75, 169, 973, 977, 1051, 1465, 1471, 1481
 
-- [x] 其他：9, 344, 387, 414, 485, 1295, 1346, 1464， 1470
+- [x] 其他：9, 136, 344, 387, 414, 485, 1295, 1346, 1464, 1470, 1480
 
 ## Binary Search
 - [x] 136, 278, 540
@@ -34,7 +34,7 @@ Notes, Codes and Ideas on LeetCode Problems
 - [x] Others: 206, 237, 707
 
 ## Math
-- [x] 231, 367, 1232
+- [x] 60, 231, 367, 1232
 
 ## Stack
 - [x] 402, 901, 1472