[LeetCode] Move Zeroes

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:

You must do this in-place without making a copy of the array.

Minimize the total number of operations.

解题思路

用两个指针i，j分别指向0和非零，当j指向非零时，交换两个指针所指向的元素，并且i向前走一步；j则每次循环无论是否交换都向前走一步。

实现代码

C++：

// Runtime: 20 ms
class Solution {
public:
void moveZeroes(vector<int>& nums) {
int i = 0;
int j = 0;
while (j < nums.size())
{
if (nums[j] != 0)
{
swap(nums[i], nums[j]);
i++;
}
j++;
}
}
};

Java：

// Runtime: 1 ms
public class Solution {
public void moveZeroes(int[] nums) {
int i = 0;
int j = 0;
while (j < nums.length) {
if (nums[j] != 0) {
if (j != i) {
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
}
i++;
}
j++;
}
}
}