1323. Maximum 69 Number -with java- (leetcode.com)

Solution.java

/*
Your runtime beats 100.00 % of java submissions.
Your memory usage beats 68.73 % of java submissions.
*/

class Solution {
    public int maximum69Number (int num){
        int n = num;
        int c = 0;
        int d = 1;
        while (n>0) {
            if (n%10 == 6)
                c = 3*d;
            n = n/10;
            d = d*10;
        }
        return num + c;
        }
}