Find duplicates under given constraints
A sorted array contains 6 different numbers, only 1 number is repeated five times. So there are total 10 numbers in array. Find the duplicate numbers using two comparisons only.
Examples :
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
Asked in Yahoo
An important observation is, arr[4] or arr[5] is an occurrence of repeated element for sure. Below is the implementation based on this observation.
CPP
// C++ program to find duplicate element under
// given constraints.
#include<bits/stdc++.h>
using namespace std;
// This function assumes array is sorted, has
// 10 elements, there are totoal 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 totoal 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
# totoal 6 different elements and one
# element repeats 5 times.
def findDuplicate(a):
if (a[3] == a[4]):
return a[3]
elif (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 totoal 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
<?php
// PHP program to find duplicate
// element under given constraints.
// This function assumes array is
// sorted, has 10 elements, there
// are totoal 6 different elements
// and one element repeats 5 times.
function 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
$a = array(1, 1, 1, 1, 1,
5, 7, 10, 20, 30);
echo findDuplicate($a);
// This code is contributed by nitin mittal.
?>
Javascript
<script>
// JavaScript program to find duplicate element under
// given constraints.
// This function assumes array is sorted, has
// 10 elements, there are totoal 6 different
// elements and one element repeats 5 times.
function 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
let a = [1, 1, 1, 1, 1, 5, 7, 10, 20, 30];
document.write(findDuplicate(a));
</script>
Output :
1
Exercise: Extend the above problem for an array with n different elements, size of array is 2*(n-1) and one element repeats (n-1) times.
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