# Min and Max in a List in Java

Given an unsorted list of integers, find maximum and minimum values in it.

Input : list = [10, 4, 3, 2, 1, 20]
Output : max = 20, min = 1

Input : list = [10, 400, 3, 2, 1, -1]
Output : max = 400, min = -1

Sorting

This is least efficient approach but will get the work done. The idea is to sort the list in natural order, then the first or last element would be the minimum and maximum element respectively. Below’s the implementation in Java.

Implementation:

## JAVA

 // This java program find minimum and maximum value // of an unsorted list of Integer by using Collection import java.util.ArrayList; import java.util.Collections; import java.util.List;   public class GFG {       // function to find minimum value in an unsorted     // list in Java using Collection     public static Integer findMin(List list)     {           // check list is empty or not         if (list == null || list.size() == 0) {             return Integer.MAX_VALUE;         }           // create a new list to avoid modification         // in the original list         List sortedlist = new ArrayList<>(list);           // sort list in natural order         Collections.sort(sortedlist);           // first element in the sorted list         // would be minimum         return sortedlist.get(0);     }       // function return maximum value in an unsorted     // list in Java using Collection     public static Integer findMax(List list)     {           // check list is empty or not         if (list == null || list.size() == 0) {             return Integer.MIN_VALUE;         }           // create a new list to avoid modification         // in the original list         List sortedlist = new ArrayList<>(list);           // sort list in natural order         Collections.sort(sortedlist);           // last element in the sorted list would be maximum         return sortedlist.get(sortedlist.size() - 1);     }       public static void main(String[] args)     {           // create an ArrayList Object list         List list = new ArrayList<>();           // add element in ArrayList object list         list.add(44);         list.add(11);         list.add(22);         list.add(33);           // print min and max value of ArrayList         System.out.println("Min: " + findMin(list));         System.out.println("Max: " + findMax(list));     } }

Output
Min: 11
Max: 44

Collections.max()

Collections.min() method return the minimum element in the specified collection and Collections.max () returns the maximum element in the specified collection, according to the natural ordering of its elements.

Implementation:

## JAVA

 // This java program find minimum and maximum value // of an unsorted list of Integer by using Collection import java.util.ArrayList; import java.util.Collections; import java.util.List;   public class GFG {       // function to find minimum value in an unsorted     // list in Java using Collection     public static Integer findMin(List list)     {           // check list is empty or not         if (list == null || list.size() == 0) {             return Integer.MAX_VALUE;         }           // return minimum value of the ArrayList         return Collections.min(list);     }       // function return maximum value in an unsorted     // list in Java using Collection     public static Integer findMax(List list)     {           // check list is empty or not         if (list == null || list.size() == 0) {             return Integer.MIN_VALUE;         }           // return maximum value of the ArrayList         return Collections.max(list);     }       public static void main(String[] args)     {           // create an ArrayList Object list         List list = new ArrayList<>();           // add element in ArrayList object list         list.add(44);         list.add(11);         list.add(22);         list.add(33);           // print min and max value of ArrayList         System.out.println("Min: " + findMin(list));         System.out.println("Max: " + findMax(list));     } }

Output
Min: 11
Max: 44

Naive

Here is naive way of finding find minimum and maximum value in an unsorted list where we check against all values present in the list and maintain minimum & maximum value found so far.

Implementation:

## JAVA

 // This java program find minimum and maximum value // of an unsorted list of Integer import java.util.ArrayList; import java.util.List;   public class GFG {       // Naive function to find minimum value in an     // unsorted list in Java     public static Integer findMin(List list)     {         // initialize min to some maximum value         Integer min = Integer.MAX_VALUE;           // loop through every element in the list and         // compare min found so far with current value         for (Integer i : list) {               // update min if found to be more than             // the current element             if (min > i) {                 min = i;             }         }           return min;     }       // This function return maximum value in an     // unsorted list in Java     public static Integer findMax(List list)     {         // initialize max variable to minimum value         Integer max = Integer.MIN_VALUE;           // loop for compare to current max value         // with all list element and find maximum value         for (Integer i : list) {               // update max if found to be less than             // the current element             if (max < i) {                 max = i;             }         }           return max;     }       public static void main(String[] args)     {         // create an ArrayList Object list         List list = new ArrayList<>();         // add element in ArrayList object list         list.add(44);         list.add(11);         list.add(22);         list.add(33);           // print min and max value of ArrayList         System.out.println("Min: " + findMin(list));         System.out.println("Max: " + findMax(list));     } }

Output
Min: 11
Max: 44

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