index.js

/*
 * @lc app=leetcode id=80 lang=javascript
 *
 * [80] Remove Duplicates from Sorted Array II
 *
 * https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/description/
 *
 * algorithms
 * Medium (39.33%)
 * Total Accepted:    238.8K
 * Total Submissions: 562.7K
 * Testcase Example:  '[1,1,1,2,2,3]'
 *
 * Given a sorted array nums, remove the duplicates in-place such that
 * duplicates appeared at most twice and return 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.
 * 
 * Example 1:
 * 
 * 
 * Given nums = [1,1,1,2,2,3],
 * 
 * Your function should return length = 5, with the first five elements of nums
 * being 1, 1, 2, 2 and 3 respectively.
 * 
 * It doesn't matter what you leave beyond the returned length.
 * 
 * Example 2:
 * 
 * 
 * Given nums = [0,0,1,1,1,1,2,3,3],
 * 
 * Your function should return length = 7, with the first seven elements of
 * nums being modified to 0, 0, 1, 1, 2, 3 and 3 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 by reference, 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]);
 * }
 * 
 * 
 */
/**
 * @param {number[]} nums
 * @return {number}
 */
var removeDuplicates = function(nums) {
    let i = 0;
    let j = 1;
    while (j < nums.length) {
        if (nums[i] === nums[j]) {
            if (j - i > 1) {
              nums.splice(j, 1);
            } else {
                j++;
            }
        } else {
          j++;
          i++;
        }
    }
    return nums.length;
};

console.log(removeDuplicates([1,1,1,2,2,3]));
console.log(removeDuplicates([0,0,1,1,1,1,2,3,3]));

module.exports = {
    id:'80',
    title:'Remove Duplicates from Sorted Array II',
    url:'https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/description/',
    difficulty:'Medium',
}