LeetCode | Plus One

题目

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.
分析
这题也没啥特别技巧吧，别用除法、取余的操作就好

代码

import java.util.ArrayList;

public class PlusOne {
public int[] plusOne(int[] digits) {
if (digits == null || digits.length == 0) {
return digits;
}
ArrayList<Integer> list = new ArrayList<Integer>();
int carry = 1;
for (int i = digits.length - 1; i >= 0; --i) {
if (carry == 1 && digits[i] == 9) {
list.add(0);
} else {
list.add(digits[i] + carry);
carry = 0;
}
}
if (carry == 1) {
list.add(1);
}
int N = list.size();
int[] results = new int
;
for (int i = 0; i < N; ++i) {
results[i] = list.get(N - 1 - i);
}
return results;
}
}