[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.

方法一：时间复杂度O(N^2)

public class Solution {
public void moveZeroes(int[] nums) {
if (nums == null || nums.length == 1) {
return;
}

int zeroCount = 0;
int zeroSequenceLength = 0;
for (int i = 0; i < nums.length - zeroCount; i++) {
if (0 == nums[i]) {
++zeroSequenceLength;
} else {
if (zeroSequenceLength >= 1) {
for (int j = i; j < nums.length - zeroCount; j++) {
nums[j - zeroSequenceLength] = nums[j];
}

zeroCount += zeroSequenceLength;
i = i - zeroSequenceLength;
zeroSequenceLength = 0;
}
}
}
for (int k = nums.length - 1; k > nums.length - 1 - zeroCount; k--) {
nums[k] = 0;
}
}
}

方法二：时间复杂度O(N)

public class Solution {
public void moveZeroes(int[] nums) {
int newIndex = 0;

for (int i = 0; i < nums.length ; i++) {
if (nums[i] != 0) {
nums[newIndex++] = nums[i];
}
}
for (; newIndex < nums.length; newIndex++) {
nums[newIndex] = 0;
}
}
}