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Find Second largest element in an array | Set 2

Largest element in an Array

Last Updated : 27 Dec, 2024

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Given an array arr. The task is to find the largest element in the given array.

Examples:

Input: arr[] = [10, 20, 4]
Output: 20
Explanation: Among 10, 20 and 4, 20 is the largest.

Input: arr[] = [20, 10, 20, 4, 100]
Output: 100

Table of Content

Iterative Approach – O(n) Time and O(1) Space

The approach to solve this problem is to traverse the whole array and find the maximum among them.

C++

#include <iostream> #include <vector> using namespace std;  int largest(vector<int>& arr) {     int max = arr[0];      //Traverse  from second and compare     // every element with current max     for (int i = 1; i < arr.size(); i++)         if (arr[i] > max)             max = arr[i];      return max; }  int main() {     vector<int> arr = {10, 324, 45, 90, 9808};     cout << largest(arr);     return 0; }

C

#include <stdio.h>  int largest(int arr[], int n) {     int i;     int max = arr[0];      // Traverse array elements from second and     // compare every element with current max     for (i = 1; i < n; i++)         if (arr[i] > max)             max = arr[i];      return max; }  int main() {     int arr[] = { 10, 324, 45, 90, 9808 };     int n = sizeof(arr) / sizeof(arr[0]);        printf("%d", largest(arr, n));     return 0; }

Java

import java.io.*;  class GfG {     static int largest(int[] arr) {         int max = arr[0];          // Traverse array elements from second and         // compare every element with current max         for (int i = 1; i < arr.length; i++)             if (arr[i] > max)                 max = arr[i];          return max;     }      public static void main(String[] args) {         int arr[] = { 10, 324, 45, 90, 9808 };         System.out.println(largest(arr));     } }

Python

def largest(arr, n):     mx = arr[0]      # Traverse array elements from second     # and compare every element with     # current max     for i in range(1, n):         if arr[i] > mx:             mx = arr[i]      return mx  if __name__ == '__main__':     arr = [10, 324, 45, 90, 9808]     n = len(arr)          ans = largest(arr, n)          print(ans)

C#

using System; using System.Collections.Generic;  class GfG {     static int Largest(List<int> arr) {         int max = arr[0];          // Traverse from second and compare         // every element with current max         for (int i = 1; i < arr.Count; i++)             if (arr[i] > max)                 max = arr[i];          return max;     }      static void Main() {         List<int> arr = new List<int> { 10, 324, 45, 90, 9808 };         Console.WriteLine(Largest(arr));     } }

JavaScript

function largest(arr) {     let max = arr[0];      // Traverse from second and compare     // every element with current max     for (let i = 1; i < arr.length; i++)         if (arr[i] > max)             max = arr[i];      return max; }  // Driver Code const arr = [10, 324, 45, 90, 9808]; console.log(largest(arr));

Output

Recursive Approach – O(n) Time and O(n) Space

The idea is similar to the iterative approach. Here the traversal of the array is done recursively instead of an iterative loop.

C++

#include <iostream> #include <vector> using namespace std;  int findMax(vector<int>& arr, int i) {       // Last index returns the element     if (i == arr.size() - 1) {         return arr[i];     }      // Find the maximum from the rest of the vector     int recMax = findMax(arr, i + 1);      // Compare with i-th element and return     return max(recMax, arr[i]); }  int largest(vector<int>& arr) {   return findMax(arr,0); }  int main() {     vector<int> arr = {10, 324, 45, 90, 9808};     cout << largest(arr);     return 0; }

C

#include <stdio.h>  int findMax(int arr[], int size, int i) {        // Last index returns the element     if (i == size - 1) {         return arr[i];     }      // Find the maximum from the rest of the array     int recMax = findMax(arr, size, i + 1);      // Compare with i-th element and return     return (recMax > arr[i]) ? recMax : arr[i]; }  int largest(int arr[], int size) {     return findMax(arr, size, 0); }  int main() {     int arr[] = {10, 324, 45, 90, 9808};     int size = sizeof(arr) / sizeof(arr[0]);     printf("%d", largest(arr, size));     return 0; }

Java

import java.util.Arrays;  class GfG {     static int findMax(int[] arr, int i) {                // Last index returns the element         if (i == arr.length - 1) {             return arr[i];         }          // Find the maximum from the rest of the array         int recMax = findMax(arr, i + 1);          // Compare with i-th element and return         return Math.max(recMax, arr[i]);     }      static int largest(int[] arr) {         return findMax(arr, 0);     }      public static void main(String[] args) {         int[] arr = {10, 324, 45, 90, 9808};         System.out.println(largest(arr));     } }

Python

def findMax(arr, i):        # Last index returns the element     if i == len(arr) - 1:         return arr[i]      # Find the maximum from the rest of the list     recMax = findMax(arr, i + 1)      # Compare with i-th element and return     return max(recMax, arr[i])   def largest(arr):     return findMax(arr, 0)  if __name__ == '__main__':   arr = [10, 324, 45, 90, 9808]   print(largest(arr))

C#

using System;  class GfG {     static int FindMax(int[] arr, int i) {                // Last index returns the element         if (i == arr.Length - 1) {             return arr[i];         }          // Find the maximum from the rest of the array         int recMax = FindMax(arr, i + 1);          // Compare with i-th element and return         return Math.Max(recMax, arr[i]);     }      static int Largest(int[] arr) {         return FindMax(arr, 0);     }      static void Main() {         int[] arr = {10, 324, 45, 90, 9808};         Console.WriteLine(Largest(arr));     } }

JavaScript

function findMax(arr, i) {     // Last index returns the element     if (i === arr.length - 1) {         return arr[i];     }      // Find the maximum from the rest of the array     let recMax = findMax(arr, i + 1);      // Compare with i-th element and return     return Math.max(recMax, arr[i]); }  function largest(arr) {     return findMax(arr, 0); }  // Driver Code const arr = [10, 324, 45, 90, 9808]; console.log(largest(arr));

Output

Using Library Methods – O(n) Time and O(1) Space

Most of the languages have a relevant max() type in-built function to find the maximum element, such as std::max_element in C++. We can use this function to directly find the maximum element.

C++

#include <iostream> #include <vector> #include <algorithm> using namespace std;  int largest(vector<int>& arr) {     return *max_element(arr.begin(), arr.end()); }  int main() {     vector<int> arr = {10, 324, 45, 90, 9808};     cout << largest(arr);     return 0; }

C

#include <stdio.h> #include <stdlib.h>  int compare(const void* a, const void* b) {     return (*(int*)a - *(int*)b); }  int largest(int arr[], int n) {     qsort(arr, n, sizeof(int), compare);     return arr[n - 1]; }  int main() {     int arr[] = {10, 324, 45, 90, 9808};     int n = sizeof(arr) / sizeof(arr[0]);     printf("%d\n", largest(arr, n));     return 0; }

Java

import java.io.*; import java.util.*;  class GfG {      static int largest(int[] arr) {         Arrays.sort(arr);         return arr[arr.length - 1];     }      static public void main(String[] args) {         int[] arr = { 10, 324, 45, 90, 9808 };         System.out.println(largest(arr));     } }

Python

# Python program to find maximum in arr[] of size n  def largest(arr):     return max(arr)  if __name__ == '__main__':   arr = [10, 324, 45, 90, 9808]   print(largest(arr))

C#

using System; using System.Linq; using System.Collections.Generic;  class GfG {   static int largest(List<int> arr) {           return arr.Max();       }        static public void Main() {  		List<int> arr = new List<int> { 10, 324, 45, 90, 9808 };         Console.WriteLine(largest(arr));     } }

JavaScript

// Function to find the largest number in an array function largest(arr) {     return Math.max(...arr); }  // Driver Code const arr = [10, 324, 45, 90, 9808]; console.log(largest(arr));

Output

Find Second largest element in an array | Set 2

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