feat: add python and java solutions to leetcode problem: No.0202

Author: yanglbme

solution/0200-0299/0202.Happy Number/README.md

@@ -31,15 +31,47 @@
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```python
-
+class Solution:
+    def isHappy(self, n: int) -> bool:
+        def get_next(n):
+            s = 0
+            while n > 0:
+                n, digit = divmod(n, 10)
+                s += digit ** 2
+            return s
+
+        visited = set()
+        while n != 1 and n not in visited:
+            visited.add(n)
+            n = get_next(n)
+        return n == 1
 ```
 
 ### **Java**
 
 <!-- 这里可写当前语言的特殊实现逻辑 -->
 
 ```java
-
+class Solution {
+    public boolean isHappy(int n) {
+        Set<Integer> visited = new HashSet<>();
+        while (n != 1 && !visited.contains(n)) {
+            visited.add(n);
+            n = getNext(n);
+        }
+        return n == 1;
+    }
+
+    private int getNext(int n) {
+        int s = 0;
+        while (n > 0) {
+            int digit = n % 10;
+            s += digit * digit;
+            n /= 10;
+        }
+        return s;
+    }
+}
 ```
 
 ### **...**

solution/0200-0299/0202.Happy Number/README_EN.md

@@ -35,13 +35,45 @@
 ### **Python3**
 
 ```python
-
+class Solution:
+    def isHappy(self, n: int) -> bool:
+        def get_next(n):
+            s = 0
+            while n > 0:
+                n, digit = divmod(n, 10)
+                s += digit ** 2
+            return s
+
+        visited = set()
+        while n != 1 and n not in visited:
+            visited.add(n)
+            n = get_next(n)
+        return n == 1
 ```
 
 ### **Java**
 
 ```java
-
+class Solution {
+    public boolean isHappy(int n) {
+        Set<Integer> visited = new HashSet<>();
+        while (n != 1 && !visited.contains(n)) {
+            visited.add(n);
+            n = getNext(n);
+        }
+        return n == 1;
+    }
+
+    private int getNext(int n) {
+        int s = 0;
+        while (n > 0) {
+            int digit = n % 10;
+            s += digit * digit;
+            n /= 10;
+        }
+        return s;
+    }
+}
 ```
 
 ### **...**

solution/0200-0299/0202.Happy Number/Solution.java

@@ -1,33 +1,20 @@
 class Solution {
     public boolean isHappy(int n) {
-        if (n <= 0) return false;
-        int sum = 0;
-        while (sum != n) {
-            while (n > 0) {
-                sum += Math.pow(n % 10, 2);
-                n /= 10;
-            }
-            if (sum == 1) return true;
-            if (sum == 4) return false;
-            n = sum;
-            sum = 0;
+        Set<Integer> visited = new HashSet<>();
+        while (n != 1 && !visited.contains(n)) {
+            visited.add(n);
+            n = getNext(n);
         }
-        return false;
+        return n == 1;
     }
-}
 
-
-// 递归
-class Solution {
-    public boolean isHappy(int n) {
-        if (n <= 0) return false;
-        int sum = 0;
+    private int getNext(int n) {
+        int s = 0;
         while (n > 0) {
-            sum += Math.pow(n % 10, 2);
+            int digit = n % 10;
+            s += digit * digit;
             n /= 10;
         }
-        if (sum == 1) return true;
-        if (sum == 4) return false;
-        return isHappy(sum);
+        return s;
     }
 }

solution/0200-0299/0202.Happy Number/Solution.py

@@ -0,0 +1,14 @@
+class Solution:
+    def isHappy(self, n: int) -> bool:
+        def get_next(n):
+            s = 0
+            while n > 0:
+                n, digit = divmod(n, 10)
+                s += digit ** 2
+            return s
+        
+        visited = set()
+        while n != 1 and n not in visited:
+            visited.add(n)
+            n = get_next(n)
+        return n == 1