Remove Element

最新推荐文章于 2021-02-04 13:49:30 发布

原创最新推荐文章于 2021-02-04 13:49:30 发布 · 151 阅读

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#Two Pointers #Array #Javascript #Leetcode #Easy

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本文介绍了一种使用双指针技术在原地移除数组中特定值的方法，并返回新的长度。该方法不使用额外的存储空间，符合常数内存约束条件。通过示例展示了如何在不考虑后续元素的情况下改变数组元素顺序。

Given an array and a value, remove all instances of that value in place and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

The order of elements can be changed. It doesn't matter what you leave beyond the new length.

Example:
Given input array nums = [3,2,2,3], val = 3

Your function should return length = 2, with the first two elements of nums being 2.

Tags

Array, Two Pointers

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Using two pointers to mark new index and runner separately.

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