Find Second largest element in an array
Given an array of integers, our task is to write a program that efficiently finds the second largest element present in the array.
Example:
Input: arr[] = {12, 35, 1, 10, 34, 1} Output: The second largest element is 34. Explanation: The largest element of the array is 35 and the second largest element is 34 Input: arr[] = {10, 5, 10} Output: The second largest element is 5. Explanation: The largest element of the array is 10 and the second largest element is 5 Input: arr[] = {10, 10, 10} Output: The second largest does not exist. Explanation: Largest element of the array is 10 there is no second largest element
Simple Solution
Approach: The idea is to sort the array in descending order and then return the second element which is not equal to the largest element from the sorted array.
Implementation:
C++
// C++ program to find second largest element in an array #include <bits/stdc++.h> using namespace std; /* Function to print the second largest elements */ void print2largest( int arr[], int arr_size) { int i, first, second; /* There should be atleast two elements */ if (arr_size < 2) { printf ( " Invalid Input " ); return ; } // sort the array sort(arr, arr + arr_size); // start from second last element as the largest element // is at last for (i = arr_size - 2; i >= 0; i--) { // if the element is not equal to largest element if (arr[i] != arr[arr_size - 1]) { printf ( "The second largest element is %d\n" ,arr[i]); return ; } } printf ( "There is no second largest element\n" ); } /* Driver program to test above function */ int main() { int arr[] = { 12, 35, 1, 10, 34, 1 }; int n = sizeof (arr) / sizeof (arr[0]); print2largest(arr, n); return 0; } // This code is contributed by Aditya Kumar (adityakumar129) |
C
// C program to find second largest element in an array #include <stdio.h> #include<stdlib.h> // Compare function for qsort int cmpfunc( const void * a, const void * b) { return (*( int *)a - *( int *)b); } /* Function to print the second largest elements */ void print2largest( int arr[], int arr_size) { int i, first, second; /* There should be atleast two elements */ if (arr_size < 2) { printf ( " Invalid Input " ); return ; } // sort the array qsort (arr, arr_size, sizeof ( int ), cmpfunc); // start from second last element as the largest element // is at last for (i = arr_size - 2; i >= 0; i--) { // if the element is not // equal to largest element if (arr[i] != arr[arr_size - 1]) { printf ( "The second largest element is %d\n" ,arr[i]); return ; } } printf ( "There is no second largest element\n" ); } /* Driver program to test above function */ int main() { int arr[] = { 12, 35, 1, 10, 34, 1 }; int n = sizeof (arr) / sizeof (arr[0]); print2largest(arr, n); return 0; } // This code is contributed by Aditya Kumar (adityakumar129) |
Java
// Java program to find second largest // element in an array import java.util.*; class GFG{ // Function to print the // second largest elements static void print2largest( int arr[], int arr_size) { int i, first, second; // There should be // atleast two elements if (arr_size < 2 ) { System.out.printf( " Invalid Input " ); return ; } // Sort the array Arrays.sort(arr); // Start from second last element // as the largest element is at last for (i = arr_size - 2 ; i >= 0 ; i--) { // If the element is not // equal to largest element if (arr[i] != arr[arr_size - 1 ]) { System.out.printf( "The second largest " + "element is %d\n" , arr[i]); return ; } } System.out.printf( "There is no second " + "largest element\n" ); } // Driver code public static void main(String[] args) { int arr[] = { 12 , 35 , 1 , 10 , 34 , 1 }; int n = arr.length; print2largest(arr, n); } } // This code is contributed by gauravrajput1 |
Python3
# Python3 program to find second # largest element in an array # Function to print the # second largest elements def print2largest(arr, arr_size): # There should be # atleast two elements if (arr_size < 2 ): print ( " Invalid Input " ) return # Sort the array arr.sort # Start from second last # element as the largest # element is at last for i in range (arr_size - 2 , - 1 , - 1 ): # If the element is not # equal to largest element if (arr[i] ! = arr[arr_size - 1 ]) : print ( "The second largest element is" , arr[i]) return print ( "There is no second largest element" ) # Driver code arr = [ 12 , 35 , 1 , 10 , 34 , 1 ] n = len (arr) print2largest(arr, n) # This code is contributed by divyeshrabadiya07 |
C#
// C# program to find second largest // element in an array using System; class GFG{ // Function to print the // second largest elements static void print2largest( int []arr, int arr_size) { int i; // There should be // atleast two elements if (arr_size < 2) { Console.Write( " Invalid Input " ); return ; } // Sort the array Array.Sort(arr); // Start from second last element // as the largest element is at last for (i = arr_size - 2; i >= 0; i--) { // If the element is not // equal to largest element if (arr[i] != arr[arr_size - 1]) { Console.Write( "The second largest " + "element is {0}\n" , arr[i]); return ; } } Console.Write( "There is no second " + "largest element\n" ); } // Driver code public static void Main(String[] args) { int []arr = { 12, 35, 1, 10, 34, 1 }; int n = arr.Length; print2largest(arr, n); } } // This code is contributed by Amit Katiyar |
Javascript
<script> // Javascript program to find second largest // element in an array // Function to print the second largest elements function print2largest(arr, arr_size) { let i, first, second; // There should be atleast two elements if (arr_size < 2) { document.write( " Invalid Input " ); return ; } // sort the array arr.sort(); // start from second last element // as the largest element is at last for (i = arr_size - 2; i >= 0; i--) { // if the element is not // equal to largest element if (arr[i] != arr[arr_size - 1]) { document.write( "The second largest element is " + arr[i]); return ; } } document.write( "There is no second largest element<br>" ); } // Driver program to test above function let arr= [ 12, 35, 1, 10, 34, 1 ]; let n = arr.length; print2largest(arr, n); // This code is contributed by Surbhi Tyagi </script> |
The second largest element is 34
Complexity Analysis:
- Time Complexity: O(n log n).
Time required to sort the array is O(n log n). - Auxiliary space: O(1).
As no extra space is required.
Better Solution:
Approach: The approach is to traverse the array twice.
In the first traversal find the maximum element.
In the second traversal find the greatest element in the remaining excluding the previous greatest.
Implementation:
C++14
// C++ program to find the second largest element in the array #include <iostream> using namespace std; int secondLargest( int arr[], int n) { int largest = 0, secondLargest = -1; // finding the largest element in the array for ( int i = 1; i < n; i++) { if (arr[i] > arr[largest]) largest = i; } // finding the largest element in the array excluding // the largest element calculated above for ( int i = 0; i < n; i++) { if (arr[i] != arr[largest]) { // first change the value of second largest // as soon as the next element is found if (secondLargest == -1) secondLargest = i; else if (arr[i] > arr[secondLargest]) secondLargest = i; } } return secondLargest; } int main() { int arr[] = {10, 12, 20, 4}; int n = sizeof (arr)/ sizeof (arr[0]); int second_Largest = secondLargest(arr, n); if (second_Largest == -1) cout << "Second largest didn't exit\n" ; else cout << "Second largest : " << arr[second_Largest]; } |
Java
// Java program to find second largest // element in an array class GFG{ // Function to print the second largest elements static void print2largest( int arr[], int arr_size) { int i, first, second; // There should be atleast two elements if (arr_size < 2 ) { System.out.printf( " Invalid Input " ); return ; } int largest = second = Integer.MIN_VALUE; // Find the largest element for (i = 0 ; i < arr_size; i++) { largest = Math.max(largest, arr[i]); } // Find the second largest element for (i = 0 ; i < arr_size; i++) { if (arr[i] != largest) second = Math.max(second, arr[i]); } if (second == Integer.MIN_VALUE) System.out.printf( "There is no second " + "largest element\n" ); else System.out.printf( "The second largest " + "element is %d\n" , second); } // Driver code public static void main(String[] args) { int arr[] = { 12 , 35 , 1 , 10 , 34 , 1 }; int n = arr.length; print2largest(arr, n); } } // This code is contributed by Amit Katiyar |
Python3
# Python3 program to find # second largest element # in an array # Function to print # second largest elements def print2largest(arr, arr_size): # There should be atleast # two elements if (arr_size < 2 ): print ( " Invalid Input " ); return ; largest = second = - 2454635434 ; # Find the largest element for i in range ( 0 , arr_size): largest = max (largest, arr[i]); # Find the second largest element for i in range ( 0 , arr_size): if (arr[i] ! = largest): second = max (second, arr[i]); if (second = = - 2454635434 ): print ( "There is no second " + "largest element" ); else : print ( "The second largest " + "element is \n" , second); # Driver code if __name__ = = '__main__' : arr = [ 12 , 35 , 1 , 10 , 34 , 1 ]; n = len (arr); print2largest(arr, n); # This code is contributed by shikhasingrajput |
C#
// C# program to find second largest // element in an array using System; class GFG{ // Function to print the second largest elements static void print2largest( int []arr, int arr_size) { // int first; int i, second; // There should be atleast two elements if (arr_size < 2) { Console.Write( " Invalid Input " ); return ; } int largest = second = int .MinValue; // Find the largest element for (i = 0; i < arr_size; i++) { largest = Math.Max(largest, arr[i]); } // Find the second largest element for (i = 0; i < arr_size; i++) { if (arr[i] != largest) second = Math.Max(second, arr[i]); } if (second == int .MinValue) Console.Write( "There is no second " + "largest element\n" ); else Console.Write( "The second largest " + "element is {0}\n" , second); } // Driver code public static void Main(String[] args) { int []arr = { 12, 35, 1, 10, 34, 1 }; int n = arr.Length; print2largest(arr, n); } } // This code is contributed by Amit Katiyar |
Javascript
<script> // Javascript program to find second largest // element in an array // Function to print the second largest elements function print2largest(arr, arr_size) { let i; let largest = second = -2454635434; // There should be atleast two elements if (arr_size < 2) { document.write( " Invalid Input " ); return ; } // finding the largest element for (i = 0;i<arr_size;i++){ if (arr[i]>largest){ largest = arr[i]; } } // Now find the second largest element for (i = 0 ;i<arr_size;i++){ if (arr[i]>second && arr[i]<largest){ second = arr[i]; } } if (second == -2454635434){ document.write( "There is no second largest element<br>" ); } else { document.write( "The second largest element is " + second); return ; } } // Driver program to test above function let arr= [ 12, 35, 1, 10, 34, 1 ]; let n = arr.length; print2largest(arr, n); </script> |
Second largest : 12
Complexity Analysis:
- Time Complexity: O(n).
Two traversals of the array is needed. - Auxiliary space: O(1).
As no extra space is required.
Efficient Solution:
Approach: Find the second largest element in a single traversal.
Below is the complete algorithm for doing this:
1) Initialize the first as 0(i.e, index of arr[0] element 2) Start traversing the array from array[1], a) If the current element in array say arr[i] is greater than first. Then update first and second as, second = first first = arr[i] b) If the current element is in between first and second, then update second to store the value of current variable as second = arr[i] 3) Return the value stored in second.
Implementation:
C
// C program to find second largest // element in an array #include <limits.h> #include <stdio.h> /* Function to print the second largest elements */ void print2largest( int arr[], int arr_size) { int i, first, second; /* There should be atleast two elements */ if (arr_size < 2) { printf ( " Invalid Input " ); return ; } first = second = INT_MIN; for (i = 0; i < arr_size; i++) { /* If current element is greater than first then update both first and second */ if (arr[i] > first) { second = first; first = arr[i]; } /* If arr[i] is in between first and second then update second */ else if (arr[i] > second && arr[i] != first) second = arr[i]; } if (second == INT_MIN) printf ( "There is no second largest element\n" ); else printf ( "The second largest element is %d" , second); } /* Driver program to test above function */ int main() { int arr[] = { 12, 35, 1, 10, 34, 1 }; int n = sizeof (arr) / sizeof (arr[0]); print2largest(arr, n); return 0; } |
C++
// C++ program to find the second largest element #include <iostream> using namespace std; // returns the index of second largest // if second largest didn't exist return -1 int secondLargest( int arr[], int n) { int first = 0, second = -1; for ( int i = 1; i < n; i++) { if (arr[i] > arr[first]) { second = first; first = i; } else if (arr[i] < arr[first]) { if (second == -1 || arr[second] < arr[i]) second = i; } } return second; } int main() { int arr[] = {10, 12, 20, 4}; int index = secondLargest(arr, sizeof (arr)/ sizeof (arr[0])); if (index == -1) cout << "Second Largest didn't exist" ; else cout << "Second largest : " << arr[index]; } |
Java
// JAVA Code for Find Second largest // element in an array class GFG { /* Function to print the second largest elements */ public static void print2largest( int arr[], int arr_size) { int i, first, second; /* There should be atleast two elements */ if (arr_size < 2 ) { System.out.print( " Invalid Input " ); return ; } first = second = Integer.MIN_VALUE; for (i = 0 ; i < arr_size; i++) { /* If current element is greater than first then update both first and second */ if (arr[i] > first) { second = first; first = arr[i]; } /* If arr[i] is in between first and second then update second */ else if (arr[i] > second && arr[i] != first) second = arr[i]; } if (second == Integer.MIN_VALUE) System.out.print( "There is no second largest" + " element\n" ); else System.out.print( "The second largest element" + " is " + second); } /* Driver program to test above function */ public static void main(String[] args) { int arr[] = { 12 , 35 , 1 , 10 , 34 , 1 }; int n = arr.length; print2largest(arr, n); } } // This code is contributed by Arnav Kr. Mandal. |
Python3
# Python program to # find second largest # element in an array # Function to print the # second largest elements def print2largest(arr, arr_size): # There should be atleast # two elements if (arr_size < 2 ): print ( " Invalid Input " ) return first = second = - 2147483648 for i in range (arr_size): # If current element is # smaller than first # then update both # first and second if (arr[i] > first): second = first first = arr[i] # If arr[i] is in # between first and # second then update second elif (arr[i] > second and arr[i] ! = first): second = arr[i] if (second = = - 2147483648 ): print ( "There is no second largest element" ) else : print ( "The second largest element is" , second) # Driver program to test # above function arr = [ 12 , 35 , 1 , 10 , 34 , 1 ] n = len (arr) print2largest(arr, n) # This code is contributed # by Anant Agarwal. |
C#
// C# Code for Find Second largest // element in an array using System; class GFG { // Function to print the // second largest elements public static void print2largest( int [] arr, int arr_size) { int i, first, second; // There should be atleast two elements if (arr_size < 2) { Console.WriteLine( " Invalid Input " ); return ; } first = second = int .MinValue; for (i = 0; i < arr_size; i++) { // If current element is smaller than // first then update both first and second if (arr[i] > first) { second = first; first = arr[i]; } // If arr[i] is in between first // and second then update second else if (arr[i] > second && arr[i] != first) second = arr[i]; } if (second == int .MinValue) Console.Write( "There is no second largest" + " element\n" ); else Console.Write( "The second largest element" + " is " + second); } // Driver Code public static void Main(String[] args) { int [] arr = { 12, 35, 1, 10, 34, 1 }; int n = arr.Length; print2largest(arr, n); } } // This code is contributed by Parashar. |
PHP
<?php // PHP program to find second largest // element in an array // Function to print the // second largest elements function print2largest( $arr , $arr_size ) { // There should be atleast // two elements if ( $arr_size < 2) { echo ( " Invalid Input " ); return ; } $first = $second = PHP_INT_MIN; for ( $i = 0; $i < $arr_size ; $i ++) { // If current element is // smaller than first // then update both // first and second if ( $arr [ $i ] > $first ) { $second = $first ; $first = $arr [ $i ]; } // If arr[i] is in // between first and // second then update // second else if ( $arr [ $i ] > $second && $arr [ $i ] != $first ) $second = $arr [ $i ]; } if ( $second == PHP_INT_MIN) echo ( "There is no second largest element\n" ); else echo ( "The second largest element is " . $second . "\n" ); } // Driver Code $arr = array (12, 35, 1, 10, 34, 1); $n = sizeof( $arr ); print2largest( $arr , $n ); // This code is contributed by Ajit. ?> |
Javascript
<script> // Javascript program to find second largest // element in an array // Function to print the second largest elements function print2largest(arr, arr_size) { let i; let largest = second = -2454635434; // There should be atleast two elements if (arr_size < 2) { document.write( " Invalid Input " ); return ; } // finding the largest element for (i = 0 ;i<arr_size;i++){ if (arr[i]>largest){ second = largest ; largest = arr[i] } else if (arr[i]!=largest && arr[i]>second ){ second = arr[i]; } } if (second == -2454635434){ document.write( "There is no second largest element<br>" ); } else { document.write( "The second largest element is " + second); return ; } } // Driver program to test above function let arr= [ 12, 35, 1, 10, 34, 1 ]; let n = arr.length; print2largest(arr, n); // This code is contributed by Shaswat Singh </script> |
The second largest element is 34
Complexity Analysis:
- Time Complexity: O(n).
Only one traversal of the array is needed. - Auxiliary space: O(1).
As no extra space is required.
Related Article:
Smallest and second smallest element in an array
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