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algorithm notes: leetcode#202 happy number

admin 11月 12, 2020 0

Problem

Solution

Analysis

Python implementation

class :
    def isHappy(self, n):
        """
        :type n: int
        :rtype: bool
        """
        seen = set()
        while n not in seen:
            seen.add(n)
            n = sum(int(num) ** 2 for num in str(n))
        return n == 1

Java implementation

class  {
    public boolean isHappy(int n) {
        Set<Integer> seen = new HashSet<>();
        while(!seen.contains(n)){
            seen.add(n);
            int sum = 0;
            while(n!=0){
                sum += Math.pow(n%10,2);
                n = n/10;
            }
            n = sum;
        }
        return n==1;
    }
}

Link

202. Happy Number
(中文版) 算法笔记: 力扣#202 快乐数