[Java] Leetcode 283. Move Zeroes [Two Pointers #2]

In this video, I'm going to show you how to solve Leetcode 283. Move Zeroes which is related to Two Pointers.

In the end, you’ll have a really good understanding on how to solve Leetcode 283. Move Zeroes and questions that are similar to this Two Pointers.

[anirudhakyathsandra]

Good solution, could be a little cleaner in terms of the if statements and that base case isn't required:
class Solution {
public void moveZeroes(int[] nums) {
int left = 0;
int right = 1;
while(right < nums.length){
if(nums[left] == 0){
if(nums[right] !=0){
int temp = nums[left];
nums[left] = nums[right];
nums[right] = temp;
}
else{
right++;
}
}
else{
left++;
right++;
}
}
}
}

[DriveBreakFixRepeat]

Great solution. The way you utilized the two pointers is very intuitive to follow.

[shenth]

Probably don't need two pointer for this. Just loop through the array, move all the non-zeros to the front and then add zeros to to the remaining

[afshinpaydar]

Counting zeros is enough and we can use only one pointer to shift non zeros at the start of array:
time complexity -> O(N)
space complexity -> O(1)

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

for (int i= 0; i < nums.length; i++) {
// counting zeros
if (nums[i] == 0) {
countOfZero ++;
continue;
}
// shift non-zeros to start of array
nums[left] = nums[i];
left ++;
}
// write zeros at the end of array
while ((left < nums.length) && (countOfZero > 0)) {
nums[left] = 0;
left ++;
countOfZero --;
}

}
}

[EricProgramming]

class Solution {
public void moveZeroes(int[] nums) {
int L = 0, R = 0;
int N = nums.length;
while(R < N){
//1. anchor the L to a 0 element
if(nums[L] != 0){
L++;
R++; //L <= R
}
//2. explore the R to a non-zero element
else if(nums[R] == 0){
R++;
}
//3. swap L and R
else{
int temp = nums[R];
nums[R] = nums[L];
nums[L] = temp;
}
}
}
}

[Rob-J-BJJ]

For the else condition since Nums[L] is always zero, cant we just set nums[L] = 0, instead of nums[L] = temp

[samuelferreira]

muito bom, apesar de eu enteder pouco ingles.

[vinoddiwan]

how it handles [1, 0] case Can anyone explain it to me?