Remove Element

描述

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 by modifying the input array in-place with O(1) extra memory.

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

Example:

Given nums = [3,2,2,3], val = 3,

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


 

题解

package algorithms

//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.

// ???
func removeElement(nums []int, val int) int {
	i, n := 0, len(nums)
	for i < n {
		if nums[i] == val {
			n--
			nums[i] = nums[n]
		} else {
			i++
		}
	}
	return n
}