LeetCode Plus One

Description:

Given a non-negative number represented as an array of digits, plus one to the number.

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

前面已经做过无数类似的了，拿一个变量pre表示前面累计的和，加法的pre只有0或1，乘法则是从0-9都有可能。

import java.util.*;

public class Solution {
public int[] plusOne(int[] digits) {
int pre = 1;

for (int i = digits.length - 1; i >= 0; i--) {
digits[i] += 1;
pre = 0;
System.out.println(pre);
if (digits[i] == 10) {
digits[i] = 0;
pre = 1;
}
if (pre == 0)
return digits;
}

int[] neo = new int[digits.length + 1];
neo[0] = 1;
for (int i = 0; i < digits.length; i++)
neo[i + 1] = digits[i];

return neo;
}
}