LeetCode 66. Plus One

分析

难度 易

来源

https://leetcode.com/problems/plus-one/description/

题目

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

The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.

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

Example 1:

Input: [1,2,3]

Output: [1,2,4]

Explanation: The array represents the integer 123.

Example 2:

Input: [4,3,2,1]

Output: [4,3,2,2]

Explanation: The array represents the integer 4321.

解答

package LeetCode;

public class L66_PlusOne {
    public int[] plusOne(int[] digits) {
        int len=digits.length;
        int[] result=new int[len+1];
        /*for(int i=0;i<result.length;i++){
            System.out.println(result[i]);
        }
        System.out.println(result);*/
        int carry=1;//加1
        for(int i=len-1;i>=0;i--){//数组最高位表示数字低位，从最高位开始算
            digits[i]+=carry;
            if(digits[i]==10){
                digits[i]=0;
                carry=1;//向前进位
            }else
                carry=0;
        }
        if(carry==1){
            result[0]=carry;
            for(int i=0;i<len;i++){
                result[i+1]=digits[i];
            }
            return result;
        }else
            return digits;
    }
    public static  void main(String[] args){
        L66_PlusOne l66=new L66_PlusOne();
        int[] digits={9,8,7,6,5,4,3,2,1,0};
        int[] result=l66.plusOne(digits);
        for(int i=0;i<result.length;i++){
            System.out.print(result[i]);
        }
    }
}