Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.
For example:
Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digit, return it.
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| public class Solution {
public int addDigits(int num) {
while (num > 9) {
num = getInt(num);
}
return num;
}
private int getInt(int num) {
int result = 0;
while (num >= 10) {
result += num % 10;
num /= 10;
}
result += num;
return result;
}
}
|
a faster one
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| public class Solution {
public int addDigits(int num) {
return (num - 1) % 9 + 1;
}
}
|