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Add to Array-Form of Integer - Easy - LeetCode - MiniTV

Add to Array-Form of Integer - Easy - LeetCode - मिनी टीवी

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 <= A.length <= 10000

0 <= A[i] <= 9

0 <= K <= 10000

If A.length > 1, then A[0] != 0

 

Solution:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LeetCode.AskGif.Easy.Array
{
    public class AddToArrayFormSoln
    {
        public IList<int> AddToArrayForm(int[] A, int K)
        {           
            var res = new List<int>();
            int i = A.Length - 1;
            int carry = 0;
            int a = 0;
            int b = 0;
            int num = 0;
            while (true)
            {
                a = 0;
                b = 0;

                if (i < 0 && K <= 0)
                {
                    break;
                }

                if (i >= 0)
                {
                    a = A[i];                    
                }
                i--;

                if (K > 0)
                {
                    b = K % 10;
                    K = K / 10;
                }

                num = a + b + carry;
                if (num > 9)
                {
                    res.Add(num % 10);
                    carry = num / 10;
                }
                else
                {
                    res.Add(num);
                    carry = 0;
                }                                
            }

            if(carry > 0)
            {
                res.Add(carry);
            }

            res.Reverse();

            return res;
        }
    }
}

 

Time Complexity: O(n)

Space Complexity: O(n) to store the result.

 

Unit Tests:

using LeetCode.AskGif.Easy.Array;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.Array
{
    [TestClass]
    public class AddToArrayFormSolnTests
    {
        [TestMethod]
        public void AddToArrayFormSoln_First()
        {
            var arr = new int[] { 1, 2, 0, 0 };
            var K = 34;
            var expected = new int[] { 1, 2, 3, 4 };

            var res = new AddToArrayFormSoln().AddToArrayForm(arr, K);
            AreEqual(expected, res);
        }

        [TestMethod]
        public void AddToArrayFormSoln_Second()
        {
            var arr = new int[] { 2, 7, 4 };
            var K = 181;
            var expected = new int[] { 4, 5, 5 };

            var res = new AddToArrayFormSoln().AddToArrayForm(arr, K);
            AreEqual(expected, res);
        }

        [TestMethod]
        public void AddToArrayFormSoln_Third()
        {
            var arr = new int[] { 2, 1, 5 };
            var K = 806;
            var expected = new int[] { 1, 0, 2, 1 };

            var res = new AddToArrayFormSoln().AddToArrayForm(arr, K);
            AreEqual(expected, res);
        }

        [TestMethod]
        public void AddToArrayFormSoln_Fourth()
        {
            var arr = new int[] { 9, 9, 9, 9, 9, 9, 9, 9, 9, 9 };
            var K = 1;
            var expected = new int[] { 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };

            var res = new AddToArrayFormSoln().AddToArrayForm(arr, K);
            AreEqual(expected, res);
        }

        private void AreEqual(int[] res, IList<int> output)
        {
            Assert.AreEqual(res.Length, output.Count);
            for (int i = 0; i < res.Length; i++)
            {
                Assert.AreEqual(res[i], output[i]);
            }
        }
    }
}