26 Remove Duplicates from Sorted Array

1. Question

Given a sorted array, remove the duplicates in-place such 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 array in-place with O(1) extra memory.
Example:
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Given nums = [1,1,2],
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Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.
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It doesn't matter what you leave beyond the new length.
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2. Implementation

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class Solution {
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public int removeDuplicates(int[] nums) {
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if (nums.length < 2) {
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return nums.length;
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}
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int index = 1;
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for (int i = 1; i < nums.length; i++) {
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if (nums[i - 1] != nums[i]) {
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nums[index++] = nums[i];
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}
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}
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return index;
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}
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}
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3. Time & Space Complexity

时间复杂度O(n), 空间复杂度O(1)