# 283. 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.
Example:
Input: [0,1,0,3,12]
Output: [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.
# Solution
Approach 1: Two pointers with sub-optimal operation.
Approach 2: Two pointers with optimal operation.
# Code (Python)
Approach 2:
def moveZeroes(self, nums: List[int]) -> None:
"""
Do not return anything, modify nums in-place instead.
"""
slot = 0
for current in range(len(nums)):
if nums[current] != 0:
nums[current], nums[slot] = nums[slot], nums[current]
slot += 1
# Code (C++)
Approach 1:
class Solution {
public:
void moveZeroes(vector<int>& nums) {
int slow = 0;
int fast = 0;
while (fast < nums.size())
{
if (nums[fast] != 0)
{
nums[slow] = nums[fast];
slow++;
}
fast++;
}
while (slow < nums.size())
{
nums[slow] = 0;
slow++;
}
}
};
class Solution {
public:
void moveZeroes(vector<int>& nums) {
int nonZeroIdx = 0;
for (int i = 0; i < nums.size(); ++i)
{
while (nonZeroIdx < nums.size() && nums[nonZeroIdx] == 0)
{
nonZeroIdx++;
}
if (nonZeroIdx < nums.size())
{
nums[i] = nums[nonZeroIdx];
nonZeroIdx++;
}
else
nums[i] = 0;
}
}
};
Approach 2:
class Solution {
public:
void moveZeroes(vector<int>& nums) {
int slow = 0;
int fast = 0;
while (slow < nums.size() && fast < nums.size())
{
if (nums[slow] == 0 && nums[fast] != 0)
std::swap(nums[slow], nums[fast]);
if (nums[slow] != 0)
slow++;
fast++;
}
}
};