🚩Find Max and Min of the array🚩

Question: Write a program to return minimum and maximum in an array. Your program should make the minimum number of comparisons.

• Answer:

  Logic:

  • Iterative: ( O ^ n )
    • Declare min and max ( min = 10000000 , max = 0 )
    • iterate through every element in the array and check if it is greater than max OR lesser than min. and update accordingly
  • Tournament method:( O ^ log2n )
    • Declare min and max ( min = 10000000 , max = 0 )
    • Run two loops. 1) From arr [ 0 ] to arr [ arr.length/2 ] . 2)From arr [ arr.length/2 ] to arr[ arr.length -1 ];
    • and find max1 and min1 from the first loop and max2 and min2 from the second loop.
    • Compare max1 and max2 AND min1 and min2
    • Print the greater max and lower min
  • Sorting method:( O ^ logn ):
    • Sort the array ( here I have used inbuilt function but you can actually implement the sorting technique to solve)
    • Print arr [ 0 ] as min and arr[ arr.length - 1 ] as max

  
  import java.util.*;
  
  public class Solution{
      public static void main(String args[]){
  
          Scanner sc = new Scanner(System.in);
          int n = sc.nextInt();
          int arr[] = new int[n];
          for(int i=0; i<arr.length; i++){
              arr[i] = sc.nextInt();
          }
  
          int maxIterative = 0;
          int minIterative = 100000000;
  
          //This is Iterative method
          for(int i=0; i<arr.length; i++){
              if(arr[i]>maxIterative){
                  maxIterative = arr[i];
              }
              if(arr[i]<minIterative){
                  minIterative = arr[i];
              }
          }
  
          System.out.println("Max by iterative is: "+maxIterative);
          System.out.println("Min by iterative is: "+minIterative);
  
          //This is Tournament method
          int maxTour1 = 0;
          int maxTour2 = 0;
          int minTour1 = 100000000;
          int minTour2 = 100000000;
  
          for(int i=0; i<arr.length/2; i++){
              if(arr[i]>maxTour1){
                  maxTour1 = arr[i];
              }
              if(arr[i]<minTour1){
                  minTour1 = arr[i];
              }
          }
          for(int i=arr.length/2; i<arr.length; i++){
              if(arr[i]>maxTour2){
                  maxTour2 = arr[i];
              }
              if(arr[i]<minTour2){
                  minTour2 = arr[i];
              }
          }
          if(maxTour1<maxTour3){
              System.out.println("Max by Tournament method is: "+maxTour2);
          }else{
              System.out.println("Max by Tournament method is: "+maxTour1);
          }
          if(minTour1<minTour2){
              System.out.println("Min by Tournament method is: "+minTour1);
          }else{
              System.out.println("Min by Tournament method is: "+minTour2);
          }
  
          //This is Sorting method
          Arrays.sort(arr);
          System.out.println("Max by sorting method is: "+arr[arr.length-1]);
          System.out.println("Min by sorting method is: "+arr[0]);
  
      }
  }