Java Program to Get the Maximum Element From a Vector

Last Updated : 08 Jun, 2021

Why We Use Vector?

Till now, we have learned two ways for declaring either with a fixed size of array or size enter as per the demand of the user according to which array is allocated in memory.

int Array_name[Fixed_size] ;
int array_name[variable_size] ;

Both ways we land up wasting memory so in order to properly utilize memory optimization vectors are introduced.

Advantages Of Using Vectors

Dynamic Size
Rich Library Functions
Easy To Know Size
No Need To Pass Size
Can be returned from a function
By default initializes with default values

Rich Library Functions Includes

Find An Element
Erase An Element
Insert An Element

Here, we use rich library functions to get a maximum element.

Note: Arrays are always passed as a pointer in arrays so another parameter you must pass the size of the array but that is not required in the case of vectors.

Syntax :

In the case of Arrays

type function_Name(type arrayName[], type sizeOfArray) ;

In the case of Vectors

type function_Name(vector<type> vectorName) ;

Considering An Example given a vector, the task is to find the maximum element.

Examples:

Input: v1={1,2,3,4,5}
Output: 5
Input: v2={7,50,0,67,98}
Output: 98

Method 1: Using a Predefined Function

First, we will initialize a vector lets say v, then we will store values in that vector.
After that, we will call the predefined method called max() defined in class java.util.Collectons.
Print the max element.

Below is the implementation of the above approach.

Java

// Java Program to find maximum element
// in a vector using predefined method
  
import java.io.*;
 
// Importing Vector Class
import java.util.Collections;
 
// Importing Vector Class
import java.util.Vector;
 
class GFG {
   
    // Main Method
    public static void main(String[] args)
    {
        // initializing a Vector
        Vector<Integer> v = new Vector<Integer>();
       
        // adding values to the Vector
        v.add(7);
        v.add(50);
        v.add(0);
        v.add(67);
        v.add(98);
       
        // finding the largest element
        int n = Collections.max(v);
       
        // printing the largest element
        System.out.println(
            "The maximum value present in Vector is : "
            + n);
    }
}

Output :

The maximum value present in Vector is : 98

Worst Case Time Complexity: O(n) where n is the number of elements present in the vector.

Method 2: Comparing each element present in Vector

First, we will initialize a vector lets say v, then we will store values in that vector.
Next, we will take a variable, let us say maxNumber and assign the minimum value possible.
Traverse till the end of vector and compare each element of a vector with maxNumber.
If the element present in the vector is greater than maxNumber, then update maxNumber to that value.
Print maxNumber.

Below is the implementation of the above approach.

Java

// Java program to find largest element
// present in Vector via comparison
 
import java.io.*;
 
// Importing Vector Class
import java.util.Vector;
 
// Importing Iterator Class
import java.util.Iterator;
 
class GFG {
   
    // Main Method
    public static void main(String[] args)
    {
        // initializing vector of Integer type
        Vector<Integer> v = new Vector<Integer>();
       
        // Adding elements in vector
        v.add(1);
        v.add(2);
        v.add(3);
        v.add(4);
        v.add(5);
       
        // Assigning min value possible
        int maxValue = Integer.MIN_VALUE;
       
        // Creating an iterator to traverse through vector
        // in the beginning itr will point to index just
        // before first element
        Iterator itr = v.iterator();
       
        // See if there is any next element
        while (itr.hasNext())
        {
            // Moving iterator to next element
            int element = (Integer)itr.next();
 
            // Comparing if element is larger than maxValue
            if (element > maxValue)
            {
                // Update maxValue
                maxValue = element;
            }
        }
       
        // Print maxVaue
        System.out.println(
            "The largest element present in Vector is : "
            + maxValue);
    }
}

Output :

The largest element present in Vector is : 5

Time Complexity: O(n) where n is the number of elements present in the vector.

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Method 1: Using a Predefined Function

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Method 2: Comparing each element present in Vector

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