Maximum

algorithm.md

###Maximum in a List - A linear approach

MAX(array):
	
	maximum = - INFINITY /* Assign the lowest possible value */
	FOR i = 0 TO (array.length - 1)
		IF array[i] > maximum
			/* If a number greater than current maximum is encountered, */
			/* assign it as new maximum. */
			maximum = array[i]
		END IF
	END FOR

	RETURN maximum

END MAX

The loop iterates over the whole array, making it's best, average and worst an O(n).

maximum.c

/*
	MAXIMUM in array
	0 based indexing
	** for TURBO C, remove // from commented statements
*/

#include<stdio.h>
//#include<conio.h>

#define INFINITY 999

int max(int *arr, int arr_length){
	int i, maximum = -INFINITY;

	for(i = 0; i <= arr_length - 1; i++){
		if(arr[i] > maximum){
			maximum = arr[i];
		}
	}
	return maximum;
}


int main(){
	int arr[10], len;
	int i, maximum;

	printf("\nEnter length (max 10): "); scanf("%d", &len);
	printf("\nEnter %d elements one after another:\n", len);
	for(i=0; i<len; i++) scanf("%d", &arr[i]);

	printf("\nYour Array ::\n\t");
	for(i=0; i<len; i++) printf("%d  ", arr[i]);

	maximum = max(arr, len);
	printf("\nMaximum in this array: %d", maximum);
	
	printf("\n");
	//getch();
	return 0;
}

Maximum.java

/*
	MAXIMUM in array
	0 based indexing
	Save File as Maximum.java
*/

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Maximum{
	
	public static int max(int[] arr){
		/* Why static? Since we are calling from main, which itself is static */
		int maximum = -999;

		for(int i = 0; i <= arr.length - 1; i++){
			if(arr[i] > maximum){
				maximum = arr[i];
			}
		}
		return maximum;
	}

	public static void main(String s[]) throws NumberFormatException, IOException{
		BufferedReader ip = new BufferedReader(new InputStreamReader(System.in));
		
		System.out.print("\nEnter length: ");
		int len = Integer.parseInt(ip.readLine());
		
		int[] arr = new int[len];
		
		System.out.println("\nEnter "+ len +" elements one after another:");
		for(int i = 0; i < len; i++) arr[i] = Integer.parseInt(ip.readLine());
		
		System.out.println("\nYour Array :");
		for(int i = 0; i < len; i++) System.out.print(" " + arr[i]);
		
		int maximum = max(arr);
		System.out.println("\nMaximum in this array: " + maximum);
		
		System.out.println("\n");	
	}
}