[LeetCode] 283. Move Zeroes

轉自LeetCode

Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.

For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3, 12, 0, 0].

Note:

1. You must do this in-place without making a copy of the array.
2. Minimize the total number of operations.

<Solution>
這題和 Remove Element 類似

但不同的點在於，必須保持原本的順序

解題想法如下

• 先將所有非零的數，一個一個從前面按順序排好

• 剩餘的位置，全部都填 0

code 如下

Java

	class Solution {
	public void moveZeroes(int[] nums) {
	int index = 0;
	for(final int n : nums) {
	if(n != 0) {
	nums[index++] = n;
	}
	}
	while(index < nums.length) {
	nums[index++] = 0;
	}
	}
	}

view raw moveZeros.java hosted with ❤ by GitHub

或者直接swap 也是可以

kotlin

	class Solution {
	fun moveZeroes(nums: IntArray): Unit {
	var index = 0
	for(i in nums.indices) {
	if(nums[i] != 0) {
	nums[index] = nums[i].also { nums[i] = nums[index] }
	++index
	}
	}
	}
	}

view raw move_zeroes.kt hosted with ❤ by GitHub