重复值判断

小咪咪 2022-06-09 01:46 199阅读 0赞

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;
        }
    }