### Determine if a string has all unique characters

Problem Implement an algorithm to determine if a string has all the characters…

September 03, 2020

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]
```

We can keep a index variable which will keep a tab on all non-zero values.

On iteration, we can move each non-zero value to left side.

```
public void moveZeroes_simple(int[] nums) {
int left=0;
for (int i=0; i<nums.length; i++) {
if (nums[i] != 0) {
nums[left] = nums[i];
left ++;
}
}
//copy zeroes to remaining array
for (int i=left; i<nums.length; i++) {
nums[i] = 0;
}
}
```

Its `O(n)`

We can do a slight modification to above solution. The point where we just move non-zero value to left. We can do a swap as well.

```
public void moveZeroes(int[] nums) {
int left=0;
for (int i=0; i<nums.length; i++) {
if (nums[i] != 0) {
//swap
int t = nums[i];
nums[i] = nums[left];
nums[left] = t;
left ++;
}
}
}
```

Its `O(n)`

But, its better since we are not using another loop to copy zero.

Problem Implement an algorithm to determine if a string has all the characters…

Problem Statement Given a linked list, swap every two adjacent nodes and return…

Problem Statement Given a Binary tree, print out nodes in level order traversal…

This is kind of preliminary technique of sorting. And, this is the first…

Problem Statement Given a linked list, remove the n-th node from the end of list…

Problem Statement You are given a rows x cols matrix grid. Initially, you are…

In this post, we will see some of the frequently used concepts/vocabulary in…

System design interview is pretty common these days, specially if you are having…

Introduction You are given an array of integers with size N, and a number K…

Graph Topological Sorting This is a well known problem in graph world…

Problem Statement Given a Binary tree, print out nodes in level order traversal…

Problem Statement Given an array nums of n integers and an integer target, are…