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Partition Array Into Three Parts With Equal Sum - Easy - LeetCode - MiniTV

Partition Array Into Three Parts With Equal Sum - Easy - LeetCode - मिनी टीवी

Given an array A of integers, return true if and only if we can partition the array into three non-empty parts with equal sums.

Formally, we can partition the array if we can find indexes i+1 < j with (A[0] + A[1] + ... + A[i] == A[i+1] + A[i+2] + ... + A[j-1] == A[j] + A[j-1] + ... + A[A.length - 1])

 

Example 1:

Input: A = [0,2,1,-6,6,-7,9,1,2,0,1]

Output: true

Explanation: 0 + 2 + 1 = -6 + 6 - 7 + 9 + 1 = 2 + 0 + 1

 

Example 2:

Input: A = [0,2,1,-6,6,7,9,-1,2,0,1]

Output: false

 

Example 3:

Input: A = [3,3,6,5,-2,2,5,1,-9,4]

Output: true

Explanation: 3 + 3 = 6 = 5 - 2 + 2 + 5 + 1 - 9 + 4

 

Constraints:

3 <= A.length <= 50000

-10^4 <= A[i] <= 10^4

 

Solution:

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

namespace LeetCode.AskGif.Easy.Array
{
    public class CanThreePartsEqualSumSoln
    {
        public bool CanThreePartsEqualSum(int[] A)
        {
            var sum = 0;
            for (int i = 0; i < A.Length; i++)
            {
                sum += A[i];
            }

            if(sum%3 != 0)
            {
                return false;
            }

            int parts = sum / 3;
            int partsCount = 0;

            int temp = 0;
            for (int i = 0; i < A.Length; i++)
            {
                temp += A[i];
                if(temp == parts)
                {
                    temp = 0;
                    partsCount++;
                }
            }

            return temp == 0 && partsCount >= 3;
        }
    }
}

 

Time Complexity: O(n)

Space Complexity: O(1)

 

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 CanThreePartsEqualSumSolnTests
    {
        [TestMethod]
        public void CanThreePartsEqualSumSoln_First()
        {
            var arr = new int[] { 0, 2, 1, -6, 6, -7, 9, 1, 2, 0, 1 };
            var expected = true;

            var res = new CanThreePartsEqualSumSoln().CanThreePartsEqualSum(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void CanThreePartsEqualSumSoln_Second()
        {
            var arr = new int[] { 0, 2, 1, -6, 6, 7, 9, -1, 2, 0, 1 };
            var expected = false;

            var res = new CanThreePartsEqualSumSoln().CanThreePartsEqualSum(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void CanThreePartsEqualSumSoln_Third()
        {
            var arr = new int[] { 3, 3, 6, 5, -2, 2, 5, 1, -9, 4 };
            var expected = true;

            var res = new CanThreePartsEqualSumSoln().CanThreePartsEqualSum(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void CanThreePartsEqualSumSoln_Fourth()
        {
            var arr = new int[] { 1, -1, 1, -1 };
            var expected = false;

            var res = new CanThreePartsEqualSumSoln().CanThreePartsEqualSum(arr);
            Assert.AreEqual(expected, res);
        }

        [TestMethod]
        public void CanThreePartsEqualSumSoln_Fifth()
        {
            var arr = new int[] { 10, -10, 10, -10, 10, -10, 10, -10 };
            var expected = true;

            var res = new CanThreePartsEqualSumSoln().CanThreePartsEqualSum(arr);
            Assert.AreEqual(expected, res);
        }
    }
}