Plus One

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

 1 public class Solution {

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

 3         // Start typing your Java solution below

 4         // DO NOT write main() function

 5         int carry = 0;

 6         boolean sig = false;

 7         int[] result = null;

 8         if(digits == null) return null;

 9         for(int i = 0;i < digits.length; i ++){

10             if(digits[i] != 9) sig = true;

11         }

12         if(sig == false){

13             result = new int[digits.length + 1];

14             result[0] = 1;

15             return result;

16         }else{

17             result = new int[digits.length];

18             result[digits.length - 1] = digits[digits.length - 1] + 1;

19             if(result[digits.length - 1] > 9){

20                 result[digits.length - 1] -= 10;

21                 carry = 1;

22             }

23             for(int i = digits.length - 2; i > -1; i --){

24                 result[i] = digits[i] + carry;

25                 if(result[i] > 9){

26                     result[i] -= 10;

27                     carry = 1;

28                 }else{

29                     carry = 0;

30                 }

31             }

32             return result;

33         }

34     }

35 }

 Second Round:

 1 public class Solution {

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

 3         boolean sig = false;

 4         for(int i = 0; i < digits.length; i ++)

 5             if(digits[i] != 9) sig = true;

 6         if(!sig){

 7             int[] result = new int[digits.length + 1];

 8             result[0] = 1;

 9             return result;

10         }

11         int[] result = new int[digits.length];

12         int carry = 1;

13         for(int i = digits.length - 1; i > -1; i --){

14             result[i] = (digits[i] + carry) % 10;

15             carry = (digits[i] + carry) / 10;

16         }

17         return result;

18     }

19 }