Remove Duplicates from Sorted Array( 滤除数组里重复的值)

最新推荐文章于 2024-01-02 23:35:28 发布

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#code #算法珠玑 #array

本文介绍了一种在原地且仅使用常数级额外空间的方法来移除有序数组中的重复元素，确保每个元素只出现一次，并返回新的长度。示例中展示了如何将输入数组[1,2,2,3,4,5]处理为[1,2,3,4,5]并返回长度5。

/**
 * Remove Duplicates from Sorted Array
 *
 * Given a sorted array, remove the duplicates in place 
 * such that each element appear only once and return the new length.
 * you must do this in place with constant memory.
 * For example, Given input array  A = [1,1,2] ,
 * Your function should return length = 2, and  A  is now  [1,2] .
 */

// Remove Duplicates from Sorted Array
// 时间复杂度O(n)，空间复杂度O(1)
public class RemoveDuplicatesFromSortedArray {
    public static int removeDuplicates(int[] arr) {
        if(null == arr || arr.length == 0) {
            return 0;
        }
        int index = 1;
        for(int i=1; i<arr.length; i++) {
            if(arr[i] != arr[index-1]) {
                arr[index++] = arr[i];
            }
        }
        return index;
    }
    public static void main(String[] arrys) {
        System.out.println("A is [1,2,2,3,4,5]");
        int[] arr = {1,2,2,3,4,5};
        int index = removeDuplicates(arr);
        System.out.println(" length = " + index);
        System.out.print(" A is now:[");
        for(int i=0; i<index; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.print("]");
    }
}