LeetCode - Algorithms - 27. Remove Element

Problem

27. Remove Element

javascript

Array.prototype.splice()

1

© 9 Ways to Remove Elements From A JavaScript Array - Plus How to Safely Clear JavaScript Arrays - Removing Array Items By Value Using Splice

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/**
 * @param {number[]} nums
 * @param {number} val
 * @return {number}
 */
var removeElement = function(nums, val) {
    for(var i = 0; i < nums.length; i++){                 
        if ( nums[i] === val) { 
            nums.splice(i, 1); 
            i--; 
        }
    }
    return nums.length;
};

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 76 ms, faster than 85.28% of JavaScript online submissions for Remove Element.
  • Memory Usage: 38.6 MB, less than 69.26% of JavaScript online submissions for Remove Element.

2

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/**
 * @param {number[]} nums
 * @param {number} val
 * @return {number}
 */
var removeElement = function(nums, val) {
    var index=nums.indexOf(val);
    while (index !== -1) {
        index = nums.indexOf(val);
        if (index!==-1)
            nums.splice(index, 1);
    }
    return nums.length;
};

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 80 ms, faster than 65.29% of JavaScript online submissions for Remove Element.
  • Memory Usage: 38.6 MB, less than 48.89% of JavaScript online submissions for Remove Element.

3

© The Fastest Way to Remove a Specific Item from an Array in JavaScript

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/**
 * @param {number[]} nums
 * @param {number} val
 * @return {number}
 */
var removeElement = function(nums, val) {
    let index
    while((index = nums.indexOf(val)) > -1) 
    {
      nums.splice(index, 1)
    }
    return nums.length;
};

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 80 ms, faster than 65.29% of JavaScript online submissions for Remove Element.
  • Memory Usage: 38.9 MB, less than 18.66% of JavaScript online submissions for Remove Element.

Two Pointers

Translation of © Solution - Approach 1: Two Pointers

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/**
 * @param {number[]} nums
 * @param {number} val
 * @return {number}
 */
var removeElement = function(nums, val) {
    var i=0;
    for(var j=0;j<nums.length;j++) {
        if (nums[j]!=val) {
            nums[i] = nums[j];
            i++;
        }
    }
    return i;
};

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 76 ms, faster than 85.28% of JavaScript online submissions for Remove Element.
  • Memory Usage: 38.7 MB, less than 48.89% of JavaScript online submissions for Remove Element.

Java

Two Pointers

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© Solution - Approach 1: Two Pointers

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class Solution {
    public int removeElement(int[] nums, int val) {
        int i = 0;
        for (int j = 0; j < nums.length; j++) {
            if (nums[j] != val) {
                nums[i] = nums[j];
                i++;
            }
        }
        return i;
    }
}

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 0 ms, faster than 100.00% of Java online submissions for Remove Element.
  • Memory Usage: 37.6 MB, less than 48.38% of Java online submissions for Remove Element.

2

© Solution - Approach 2: Two Pointers - when elements to remove are rare

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class Solution {
    public int removeElement(int[] nums, int val) {
        int n = nums.length;
        for (int i = 0; i < n; ) {
            if (nums[i] == val) {
                nums[i] = nums[n - 1];
                n--;
            } else
                i++;
        }
        return n;
    }
}

Submission Detail

  • 113 / 113 test cases passed.
  • Runtime: 0 ms, faster than 100.00% of Java online submissions for Remove Element.
  • Memory Usage: 37.7 MB, less than 48.38% of Java online submissions for Remove Element.