Remove Duplicates from Sorted Array

Given a sorted arraynums, remove the duplicatesin-placesuch that each element appear only_once_and return the new length.

Do not allocate extra space for another array, you must do this bymodifying the input arrayin-placewith O(1) extra memory.

Example 1:

Given nums = [1,1,2],

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.

Example 2:

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

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.

Clarification:

Confused why the returned value is an integer but your answer is an array?

Note that the input array is passed in byreference, which means modification to the input array will be known to the caller as well.

Internally you can think of this:

// nums is passed in by reference. (i.e., without making a copy)
int len = removeDuplicates(nums);

// any modification to nums in your function would be known by the caller.
// using the length returned by your function, it prints the first len elements.
for (int i = 0; i < len; i++) {
    print(nums[i]);
}

Solution

class Solution {
    public int removeDuplicates(int[] nums) {
        // create current index that will a running number, increase always when another number is found - count = 0
        // iterate through the array and keep the value in current value variable (1)
        // compare if the nums[i] value is bigger than the current value
        // if yes -> write position on count, increment count++ 
        // else continue reading
        int count = 0;
        int latestValue = Integer.MIN_VALUE;
        for (int i = 0; i < nums.length; i++) {
            int num = nums[i];
            if (latestValue < num) {
                nums[count] = num;
                latestValue = num;
                count++;
            }
        }
        return count;
    }
}