在给定的约束下查找重复项

一个有序数组包含 6 个不同的数字，只有 1 个数字重复了 5 次。所以数组中共有10个数字。仅使用两次比较查找重复的数字。
例子：

Input: arr[] = {1, 1, 1, 1, 1, 5, 7, 10, 20, 30}
Output: 1

Input: arr[] = {1, 2, 3, 3, 3, 3, 3, 5, 9, 10}
Output: 3

在雅虎问

一个重要的观察是，arr[4] 或 arr[5] 肯定是重复元素的出现。以下是基于此观察的实现。

CPP

// C++ program to find duplicate element under
// given constraints.
#include
using namespace std;
 
// This function assumes array is sorted,  has
// 10 elements,  there are total 6 different
// elements and one element repeats 5 times.
int findDuplicate(int a[])
{
    if (a[3] == a[4])
        return a[3];
    else if (a[4] == a[5])
        return a[4];
    else
        return a[5];
}
 
// Driver code
int main()
{
    int a[] = {1, 1, 1, 1, 1, 5, 7, 10, 20, 30};
    cout << findDuplicate(a);
    return 0;
}

JAVA

// Java program to find duplicate element under
// given constraints.
class Num{
 
// This function assumes array is sorted, has
// 10 elements, there are total 6 different
// elements and one element repeats 5 times.
static int findDuplicate(int a[])
{
    if (a[3] == a[4])
        return a[3];
    else if (a[4] == a[5])
        return a[4];
    else
        return a[5];
}
 
// Driver code
public static void main(String[] args)
{
    int a[] = {1, 1, 1, 1, 1, 5, 7, 10, 20, 30};
    System.out.println(findDuplicate(a));
}
}
//This code is contributed by
//Smitha Dinesh Semwal

Python3

# Python 3 program to find duplicate
# element under given constraints.
 
# This function assumes array is
# sorted, has 10 elements, there are
# total 6 different elements and one
# element repeats 5 times.
def findDuplicate(a):
 
    if (a[3] == a[4]):
        return a[3]
    else if (a[4] == a[5]):
        return a[4]
    else:
        return a[5]
 
# Driver code
a = [1, 1, 1, 1, 1, 5, 7,
              10, 20, 30]
 
print(findDuplicate(a))
 
# This code is contributed by Smitha Dinesh Semwal

C#

// C# program to find duplicate 
// element under given constraints.
using System;
 
class GFG {
 
// This function assumes array is
// sorted, has 10 elements, there
// are total 6 different elements
// and one element repeats 5 times.
static int findDuplicate(int []a)
{
    if (a[3] == a[4])
        return a[3];
    else if (a[4] == a[5])
        return a[4];
    else
        return a[5];
}
 
// Driver code
public static void Main()
{
    int []a = {1, 1, 1, 1, 1, 5,
               7, 10, 20, 30};
    Console.Write(findDuplicate(a));
}
}
 
// This code is contributed by nitin mittal

PHP

Javascript

输出：