Java: Remove all occurrences of a specified value in a given array, return the new length

Last update on December 21 2024 09:54:14 (UTC/GMT +8 hours)

Remove Element in Array

Write a Java program to remove all occurrences of a specified value in a given array of integers. Return the updated array length.

Pictorial Presentation:

Sample Solution:

Java Code:

import java.util.*;

public class Solution {
    /**
     * Remove all occurrences of a given element from an array and return the new length.
     * @param nums: A list of integers
     * @param element: An integer to be removed
     * @return: The new length after removing the element
     */
    public static int removeElement(int[] nums, int elem) {
        int length = nums.length; // Get the initial length of the array
        if (length == 0) return 0; // If the array is empty, return 0 (no changes)
        
        int i = 0; // Initialize the index for the new array
        
        // Iterate through the original array
        for (int j = 0; j < length; j++) {
            if (nums[j] != elem) {
                // If the current element is not equal to the element to be removed
                // Copy it to the new position in the array
                nums[i] = nums[j];
                i++;
            }
        }
        
        // Replace elements beyond the new length with a sentinel value
        if (i < length) nums[i] = '\0';
        
        // Return the new length (the value of 'i')
        return i;
    }
    
    public static void main(String[] args) {
        int x = 6; // Element to be removed
        int[] nums = {1, 4, 6, 7, 6, 2}; // Original array
        System.out.println("Original array: " + Arrays.toString(nums));
        
        // Call the removeElement function and print the new length
        System.out.println("The length of the new array is: " + removeElement(nums, x));
    }
}

Sample Output:

Original array: [1, 4, 6, 7, 6, 2]
The length of the new array is: 4

Flowchart:

Java Code Editor:

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