LeetCode - Easy - 989. Add to Array-Form of Integer

约定不等于承诺〃 2022-11-05 06:30 119阅读 0赞

## Topic ##

*  Array

## Description ##

[https://leetcode.com/problems/add-to-array-form-of-integer/][https_leetcode.com_problems_add-to-array-form-of-integer]

For a non-negative integer `X`, the array-form of `X` is an array of its digits in left to right order. For example, if `X = 1231`, then the array form is `[1,2,3,1]`.

Given the array-form `A` of a non-negative integer `X`, return the array-form of the integer `X+K`.

**Example 1**:

Input: A = [1,2,0,0], K = 34
    Output: [1,2,3,4]
    Explanation: 1200 + 34 = 1234

**Example 2**:

Input: A = [2,7,4], K = 181
    Output: [4,5,5]
    Explanation: 274 + 181 = 455

**Example 3**:

Input: A = [2,1,5], K = 806
    Output: [1,0,2,1]
    Explanation: 215 + 806 = 1021

**Example 4**:

Input: A = [9,9,9,9,9,9,9,9,9,9], K = 1
    Output: [1,0,0,0,0,0,0,0,0,0,0]
    Explanation: 9999999999 + 1 = 10000000000

**Note**：

1.  `1 <= A.length <= 10000`
2.  `0 <= A[i] <= 9`
3.  `0 <= K <= 10000`
4.  If `A.length > 1`, then `A[0] != 0`

## Analysis ##

略

## Submission ##

import java.util.LinkedList;
    import java.util.List;
    
    public class AddToArrayFormOfInteger { 
    	public List<Integer> addToArrayForm(int[] A, int K) { 
    		List<Integer> result = new LinkedList<>();
    		int index = A.length - 1, carry = 0;
    		while (index >= 0 || K > 0 || carry == 1) { 
    			int a = index < 0 ? 0 : A[index--];
    			int b = K - (K / 10) * 10;
    			K /= 10;
    			int s = a + b + carry;
    			result.add(0, s - (carry = s / 10) * 10);
    		}
    
    		return result;
    	}
    }

## Test ##

import static org.junit.Assert.*;
    import static org.hamcrest.CoreMatchers.*;
    
    import java.util.Arrays;
    import org.junit.Test;
    
    public class AddToArrayFormOfIntegerTest { 
    
    	@Test
    	public void test() { 
    		AddToArrayFormOfInteger obj = new AddToArrayFormOfInteger();
    
    		assertThat(obj.addToArrayForm(new int[] {  1, 2, 0, 0 }, 34), is(Arrays.asList(1, 2, 3, 4)));
    		assertThat(obj.addToArrayForm(new int[] {  2, 7, 4 }, 181), is(Arrays.asList(4, 5, 5)));
    		assertThat(obj.addToArrayForm(new int[] {  2, 1, 5 }, 806), is(Arrays.asList(1, 0, 2, 1)));
    		assertThat(obj.addToArrayForm(new int[] {  9, 9, 9, 9, 9, 9, 9, 9, 9, 9 }, 1), //
    				is(Arrays.asList(1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)));
    	}
    }

[https_leetcode.com_problems_add-to-array-form-of-integer]: https://leetcode.com/problems/add-to-array-form-of-integer/