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;
}

}

转载于:https://blog.51cto.com/13545923/2054462