重复值判断

请设计一个高效算法，判断数组中是否有重复值。必须保证额外空间复杂度为O(1)。

给定一个int数组A及它的大小n，请返回它是否有重复值。

# 测试样例：[1,2,3,4,5,5,6],7返回：true

我的提交

# -*- coding:utf-8 -*-class Checker:    def checkDuplicate(self, a, n):        # write code here        a = sorted(a)        for i in range(len(a) - 1):            if a[i] == a[i+1]:                return True        return False

参考答案

class Checker:    def checkDuplicate(self, a, n):        # write code here        return len(set(a)) < n

import java.util.*;public class Checker {        public  boolean checkDuplicate(int[] a, int n) {        if (a == null || n == 0) {            return false;        }        heapSort(a);        for (int i = 1; i < n; i++) {            if (a[i] == a[i - 1]) {                return true;            }        }        return false;    }    public  void heapSort(int[] arr) {        for (int i = 0; i != arr.length; i++) {            heapInsert(arr, i);        }        for (int i = arr.length - 1; i != 0; i--) {            swap(arr, 0, i);            heapify(arr, 0, i);        }    }    public  void heapInsert(int[] arr, int index) {        while (index != 0) {            int parent = (index - 1) / 2;            if (arr[parent] < arr[index]) {                swap(arr, parent, index);                index = parent;            } else {                break;            }        }    }    public  void heapify(int[] arr, int index, int heapSize) {        int left = index * 2 + 1;        int right = index * 2 + 2;        int largest = index;        while (left < heapSize) {            if (arr[left] > arr[index]) {                largest = left;            }            if (right < heapSize && arr[right] > arr[largest]) {                largest = right;            }            if (largest != index) {                swap(arr, largest, index);            } else {                break;            }            index = largest;            left = index * 2 + 1;            right = index * 2 + 2;        }    }    public  void swap(int[] arr, int index1, int index2) {        int tmp = arr[index1];        arr[index1] = arr[index2];        arr[index2] = tmp;    }}