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+# [202. Happy Number](https://leetcode.com/problems/happy-number/description/)
+# 思路
+按照题目的意思进行循环，判断每次循环结果是否为1，若是则返回true，否则用map记录结果，然后修改n进行下一次循环。  
+# C++
+```
+class Solution {
+private:
+    int count_sum(int n){ // 定义题目中所述的求和函数
+        int sum = 0;
+        while(n > 0){
+            sum += (n % 10) * (n % 10);
+            n /= 10;
+        }
+        return sum;
+    }
+public:
+    bool isHappy(int n) {
+        map<int, int>mp;
+        while(n){
+            if(n == 1) return true;
+            if(mp[n] == 1) return false;
+            mp[n] = 1;
+            n = count_sum(n);
+        }
+        return false;
+    }
+};
+```