A Leetcode a day-----Determine if a number is happy numbers (the sum of squares of each bit is 1)

Source: Internet
Author: User
Happy number

Original title Link Happy number

For each bit of a number the sum of squares is squared and so repeated, knowing that when the following conditions are met it is a happy number a moment squared and 1 into an infinite loop

Just do as you want.

Class Solution {public
    bool Ishappy (int n) {
        if (n = = 1) {
            return true;
        if (Hash_.find (n)! = Hash_.end ()) {
            return false;
        Hash_.insert (n);
        int m = 0;
        while (n) {
            int k = n;
            n/= Ten;
            M + = k * k;
        Return Ishappy (m);
    std::unordered_set<int> hash_;

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