Remove Duplicates from Sorted Array LeetCode | Java Solution

Remove Duplicates from Sorted Array LeetCode Solution in Java

Given a sorted array nums, remove the duplicates in-place such that each element appears only once and returns the new length.

Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.

Read full description in LeetCode :-

Problem Description

So lets see solution.

Solution 1 :-

class Solution {
    public int removeDuplicates(int[] nums) {
        
    	int temp = 0;
	for (int i = 1; i<nums.length; i++) {
	   if (nums[i] != nums[temp]) {
		  temp++;
		  nums[temp] = nums[i];
	    }
	}
	return temp+1;
    }
}

Input and Output :-

Input: nums = [1,1,2]
Output: 2, nums = [1,2]
Explanation: Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It doesn't matter what you leave beyond the returned length.
Input: nums = [0,0,1,1,1,2,2,3,3,4]
Output: 5, nums = [0,1,2,3,4]
Explanation: Your function should return length = 5, with the first five elements of nums being modified to 0, 1, 2, 3, and 4 respectively. It doesn't matter what values are set beyond the returned length. 

Explanation :-

nums = [0, 0, 1, 1, 1, 2, 2, 3, 3, 4] 

• Declare and Initialize temp with 0.
• Loop through nums array from 1 to array length.
• Check current value(1st array index) is not same as 0th index.
• nums[i] != nums[temp] | nums[1] != nums[0] | 0 != 0 becomes false.
  
  
• nums[2] != nums[0] | 1 != 0 becomes true.
• Increment temp by 1 | temp = 1.
• nums[temp] = nums[i] | nums[1] = nums[2]
  
• nums = [0, 1, 1, 1, 1, 2, 2, 3, 3, 4] , temp = 1, i = 2
  
  
• nums[3] != nums[1] | 1 != 1 becomes false. temp = 1, i =3
  
  
• nums[4] != nums[1] | 1 != 1 becomes false. temp = 1, i =4
  
  
• nums[5] != nums[1] | 1 != 1 becomes true. 
• Increment temp by 1 | temp = 2.
• nums[temp] = nums[i] | nums[2] = nums[5]
  
• nums = [0, 1, 2, 1, 1, 2, 2, 3, 3, 4], temp = 2, i = 5
  
  
• nums[6] != nums[2] | 2 != 2 becomes false. temp = 2, i = 6
  
  
• nums[7] != nums[2] | 2 != 3 becomes true.
• Increment temp by 1 | temp = 3.
• nums[temp] = nums[i] | nums[3] = nums[7]
  
• nums = [0, 1, 2, 3, 1, 2, 2, 3, 3, 4], temp 3, i = 7
  
  
• nums[8] != nums[3] | 3 != 3 becomes false. temp = 3, i =8
  
  
• nums[9] != nums[3] | 4 != 3 becomes true.
• Increment temp by 1 | temp = 4.
• nums[temp] = nums[i] | nums[4] = nums[9] 
  
  
• nums = [0, 1, 2, 3, 4, 2, 2, 3, 3, 4], temp 4, i =9
• Now for loop is completed, and Output returns temp+1 means 4+1 = 5.
  

 

Happy Coding.

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