/
_0026_RemoveDuplicatesFromSortedArray.java
108 lines (102 loc) · 2.92 KB
/
_0026_RemoveDuplicatesFromSortedArray.java
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package com.diguage.algorithm.leetcode;
import java.util.Arrays;
import java.util.Objects;
/**
* = 26. Remove Duplicates from Sorted Array
*
* https://leetcode.com/problems/remove-duplicates-from-sorted-array/description/[Remove Duplicates from Sorted Array - LeetCode]
*
* Given a sorted array `nums`, remove the duplicates
* *https://en.wikipedia.org/wiki/In-place_algorithm[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 by *modifying
* the input array* *https://en.wikipedia.org/wiki/In-place_algorithm[in-place]*
* with O(1) extra memory.
*
* .Example 1:
* [source]
* ----
* 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:
* [source]
* ----
* 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 by *reference*, which means modification to the input array will be known to the caller as well.
*
* Internally you can think of this:
*
* [source]
* ----
* // 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]);
* }
* ----
*
* @author D瓜哥, https://www.diguage.com/
* @since 2018-07-19 18:34
*/
public class _0026_RemoveDuplicatesFromSortedArray {
public static int removeDuplicates(int[] nums) {
if (Objects.isNull(nums) || nums.length == 0) {
return 0;
}
int i = 0;
for (int j = 1; j < nums.length; j++) {
if (nums[i] != nums[j]) {
i++;
nums[i] = nums[j];
}
}
return i + 1;
}
public static int removeDuplicates1(int[] nums) {
if (nums == null || nums.length == 0) {
return 0;
}
int result = nums.length;
if (nums.length == 1) {
return result;
}
int previousNum = nums[0];
int minuendIndex = 0;
for (int i = 1; i < nums.length; i++) {
if (previousNum == nums[i]) {
minuendIndex++;
result--;
} else {
previousNum = nums[i];
}
if (minuendIndex > 0) {
nums[i - minuendIndex] = nums[i];
}
}
return result;
}
public static void main(String[] args) {
int[] nums = {1, 2, 2};
System.out.println(removeDuplicates(nums));
System.out.println(Arrays.toString(nums));
}
}