package com.leetcode.array;

/**

* Created by charles on 4/5/17.

* Given a non-negative integer represented as a non-empty array of digits, plus one to the integer.

You may assume the integer do not contain any leading zero, except the number 0 itself.

The digits are stored such that the most significant digit is at the head of the list.

*/

public class PlusOne_66 {

/**

* from left to right, left is high digits, right is lower digits

* like 199 + 1=> 200

* or 9 + 1 => 10

*

* Thought: from right (lowest digits) {}

* if (digit < 9) { digit++, then break;}

* else set current digit as 0

* and then to next digit, until reach at index 0

* if (digit[0] == 0) {

* need to create new array, size + 1, and assign arr[0] = 1

* }

*

*/

public int[] plusOne(int[] digits) {

int len = digits.length;

for (int i = len - 1; i >= 0; i--) {

if (digits[i] < 9) {

digits[i]++;

break;// return directly

} else {

digits[i] = 0;

}

}

// like case 99 + 1 -> 100 or 9 + 1 -> 10

if (digits[0] == 0) {

int[] res = new int[len + 1];

res[0] = 1;

return res;

}

return digits;

}

}