From dbae949f8a7f74194bb2b4aed2bba02e0a76d2f3 Mon Sep 17 00:00:00 2001
From: youngyangyang04 <826123027@qq.com>
Date: Tue, 30 Jun 2020 11:00:26 +0800
Subject: [PATCH] Update

---
 README.md                                 |  6 ++--
 problems/0202.快乐数.md                | 41 +++++++++++++++++++++++
 problems/0242.有效的字母异位词.md | 30 +++++++++++++++++
 problems/0350.两个数组的交集II.md  |  8 ++---
 4 files changed, 79 insertions(+), 6 deletions(-)
 create mode 100644 problems/0202.快乐数.md
 create mode 100644 problems/0242.有效的字母异位词.md

diff --git a/README.md b/README.md
index 20ffcb84..4de7662b 100644
--- a/README.md
+++ b/README.md
@@ -13,15 +13,17 @@ LeetCode 最强题解（持续更新中）:
 |[0053.最大子序和](https://github.com/youngyangyang04/leetcode/blob/master/problems/0053.最大子序和.md) |数组 |简单|**暴力** **贪心** 动态规划 分治|
 |[0059.螺旋矩阵II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0059.螺旋矩阵II.md) |数组 |中等|**模拟**|
 |[0083.删除排序链表中的重复元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0083.删除排序链表中的重复元素.md) |链表 |简单|**模拟**|
-|[0142.环形链表II.md](https://github.com/youngyangyang04/leetcode/blob/master/problems/0142.环形链表II.md) |链表 |中等|**模拟**|
+|[0142.环形链表II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0142.环形链表II.md) |链表 |中等|**模拟**|
+|[0202.快乐数](https://github.com/youngyangyang04/leetcode/blob/master/problems/0202.快乐数.md) |哈希表 |简单|**哈希**|
 |[0203.移除链表元素](https://github.com/youngyangyang04/leetcode/blob/master/problems/0203.移除链表元素.md) |链表 |简单|**模拟** **虚拟头结点**|
 |[0206.翻转链表](https://github.com/youngyangyang04/leetcode/blob/master/problems/0206.翻转链表.md) |链表 |简单| **模拟** **递归**|
 |[0209.长度最小的子数组](https://github.com/youngyangyang04/leetcode/blob/master/problems/0209.长度最小的子数组.md) |数组 |中等| **暴力** **滑动窗口**|
 |[0219.存在重复元素II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0219.存在重复元素II.md) | 哈希表 |简单| **哈希** |
 |[0237.删除链表中的节点](https://github.com/youngyangyang04/leetcode/blob/master/problems/0237.删除链表中的节点.md) |链表 |简单| **原链表移除** **添加虚拟节点** 递归|
+|[0242.有效的字母异位词](https://github.com/youngyangyang04/leetcode/blob/master/problems/0242.有效的字母异位词.md) |哈希表 |简单| **哈希**|
 |[0349.两个数组的交集](https://github.com/youngyangyang04/leetcode/blob/master/problems/0349.两个数组的交集.md) |哈希表 |简单|**哈希**|
 |[0350.两个数组的交集II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0350.两个数组的交集II.md) |哈希表 |简单|**哈希**|
-|[0383.赎金信](https://github.com/youngyangyang04/leetcode/blob/master/problems/0383.赎金信.md) |数组 |简单|**暴力** **字典计数**|
+|[0383.赎金信](https://github.com/youngyangyang04/leetcode/blob/master/problems/0383.赎金信.md) |数组 |简单|**暴力** **字典计数** **哈希**|
 |[0454.四数相加II](https://github.com/youngyangyang04/leetcode/blob/master/problems/0454.四数相加II.md) |哈希表 |中等| **哈希**|
 |[0575.分糖果.md](https://github.com/youngyangyang04/leetcode/blob/master/problems/0575.分糖果.md) |哈希表 |简单|**哈希**|
 |[0705.设计哈希集合.md](https://github.com/youngyangyang04/leetcode/blob/master/problems/0705.设计哈希集合.md) |哈希表 |简单|**模拟**|
diff --git a/problems/0202.快乐数.md b/problems/0202.快乐数.md
new file mode 100644
index 00000000..60c534c4
--- /dev/null
+++ b/problems/0202.快乐数.md
@@ -0,0 +1,41 @@
+# 题目地址 
+https://leetcode-cn.com/problems/happy-number/
+
+# 思路 
+
+这道题目重点是，题目中说了会 **无限循环**， 那么也就是说 求和的过程中，sum会重复出现，这对我们解题很重要，这样我们就可以使用哈希法，来判断这个sum是否重复出现，如果重复了就是return false， 否则一直找到sum为1为止
+
+还有就是求和的过程，如果对 取数值各个位上的单数操作不熟悉的话，做这道题也会比较艰难
+
+# C++代码
+
+```
+class Solution {
+public:
+    // 取和
+    int getSum(int n) {
+        int sum = 0;
+        while (n) {
+            sum += (n % 10) * (n % 10);
+            n /= 10;
+        }
+        return sum;
+    }
+    bool isHappy(int n) {
+        unordered_set<int> set;
+        while(1) {
+            int sum = getSum(n);
+            if (sum == 1) {
+                return true;
+            }
+            // 如果这个sum曾经出现过，说明已经陷入了无限循环了，立刻return false
+            if (set.find(sum) != set.end()) {
+                return false;
+            } else {
+                set.insert(sum);
+            }
+            n = sum;
+        }
+    }
+};
+```
diff --git a/problems/0242.有效的字母异位词.md b/problems/0242.有效的字母异位词.md
new file mode 100644
index 00000000..425cb805
--- /dev/null
+++ b/problems/0242.有效的字母异位词.md
@@ -0,0 +1,30 @@
+
+## 题目地址 
+
+https://leetcode-cn.com/problems/valid-anagram/
+
+## 思路
+
+使用哈希法来判断 s 中的字母是否 都在t中，且t中的字符也都在s中 
+
+## 代码
+```
+class Solution {
+public:
+    bool isAnagram(string s, string t) {
+        int record[26] = {0};
+        for (int i = 0; i < s.size(); i++) {
+            record[s[i]-'a']++;
+        }
+        for (int i = 0; i < t.size(); i++) {
+            record[t[i]-'a']--;
+        }
+        for (int i = 0; i < 26; i++) {
+            if (record[i] != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+};
+```
diff --git a/problems/0350.两个数组的交集II.md b/problems/0350.两个数组的交集II.md
index 68c2d2a1..f3cf2b19 100644
--- a/problems/0350.两个数组的交集II.md
+++ b/problems/0350.两个数组的交集II.md
@@ -18,14 +18,14 @@ class Solution {
 public:
     vector<int> intersect(vector<int>& nums1, vector<int>& nums2) {
         vector<int> result;
-        unordered_map<int, int> umap;
+        unordered_map<int, int> map;
         for (int num : nums1) {
-            umap[num]++;
+            map[num]++;
         }
         for (int num : nums2) {
-            if (umap[num] > 0) {
+            if (map[num] > 0) {
                 result.push_back(num);
-                umap[num]--;
+                map[num]--;
             }
         }
         return result;