[LeetCode]66、Plus One
题目描述：
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.
思路：
大数存储，加一。一个整数，存在一个数组中，最高位在a[0],最低位在a[a.lenth-1].要在末尾+1，如果a[a.lenth-1]<9,则直接加一返回。
如果等于9，则该位置0，往前一位继续计算。如果最高位仍是9，加一位会导致进位，则变为0，新加一位置1。
1 public class Solution66 { 2 public int[] plusOne(int[] digits){ 3 for(int i = digits.length-1;i >= 0;--i){ 4 if(digits[i]<9){ 5 ++digits[i]; 6 return digits; 7 } 8 else if(digits[i]==9){ 9 digits[i]=0; 10 } 11 } 12 int[] res = new int[digits.length+1]; 13 res[0] = 1; 14 return res; 15 } 16 public static void main(String[] args) { 17 // TODO Auto-generated method stub 18 Solution66 solution66 = new Solution66(); 19 int[] digits = {0}; 20 int[] result; 21 result= solution66.plusOne(digits); 22 for(int i = 0; i< result.length;i++){ 23 System.out.print(result[i]); 24 } 25 } 26 27 }