LeetCode Happy Number
來源:程序員人生 發布時間:2015-06-23 08:16:23 閱讀次數:3318次
1. 題目
Write an algorithm to determine if a number is "happy".
A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.
Example: 19 is a happy number
- 12 + 92 = 82
- 82 + 22 = 68
- 62 + 82 = 100
- 12 + 02 + 02 = 1
2.解題方案
class Solution {
public:
bool isHappy(int n) {
if(n < 1){
return false;
}
if(n == 1){
return true;
}
unordered_set<int> showNums;
showNums.insert(n);
while(true){
int sum = 0;
while(n != 0){
int oneDigital = n % 10;
n = n / 10;
sum = sum + oneDigital * oneDigital;
}
if(sum == 1){
return true;
}else{
if(showNums.find(sum) == showNums.end()){
showNums.insert(sum);
}else{
return false;
}
}
n = sum;
}
}
};
思路:用求余和除以10得到每位數,相加進行判斷。這里還用了1個set來存儲已出現的數字,如果重復了,說明就不是1個happy number。
http://www.waitingfy.com/archives/1678
生活不易,碼農辛苦
如果您覺得本網站對您的學習有所幫助,可以手機掃描二維碼進行捐贈