Finding Minimum Element of Java ArrayList

• Difficulty Level : Expert
• Last Updated : 04 Jan, 2021

For finding the minimum element in the ArrayList(This class is found in java.util package), complete traversal of the ArrayList is required. There is an inbuilt function in ArrayList class to find minimum element in the ArrayList, i.e. Time Complexity is O(N), where N is the size of ArrayList, Let’s discuss both the methods.

Example

```Input : ArrayList = {2, 9, 1, 3, 4}
Output: Min = 1

Input : ArrayList = {6, 7, 2, 8}
Output: Min = 2```

Approach 1:

1. Create on variable and initialize it with the first element of ArrayList.
2. Start traversing the ArrayList.
3. If the current element is less than variable, then update the variable with the current element in ArrayList.
4. In the end, print that variable.

Below is the implementation of the above approach:

Java

 `// Finding Minimum Element of Java ArrayList``import` `java.util.ArrayList;``import` `java.util.Collections;`` ` `class` `MinElementInArrayList {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{`` ` `        ` `        ``// ArrayList of Numbers  ``        ``ArrayList myList``            ``= ``new` `ArrayList();`` ` `        ``// adding elements to Java ArrayList``        ``myList.add(``16``);``        ``myList.add(``26``);``        ``myList.add(``3``);``        ``myList.add(``52``);``        ``myList.add(``70``);``        ``myList.add(``12``);`` ` `        ``int` `minimum = myList.get(``0``);``        ``for` `(``int` `i = ``1``; i < myList.size(); i++) {``            ``if` `(minimum > myList.get(i))``                ``minimum = myList.get(i);``        ``}``        ``System.out.println(``"Minimum element in ArrayList = "``                           ``+ minimum);``    ``}``}`
Output
`Minimum element in ArrayList = 3`

Approach 2:

‘min’ method of java collection class can be used to find ArrayList. ‘min’ method returns the minimum element of the collection according to the natural ordering of the elements.

Java

 `// Finding Minimum Element of Java ArrayList``import` `java.util.ArrayList;``import` `java.util.Collections;`` ` `class` `MinElementInArrayList {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{`` ` ` ` `        ``// ArrayList of Numbers``        ``ArrayList myList``            ``= ``new` `ArrayList();`` ` `        ``// adding elements to Java ArrayList``        ``myList.add(``16``);``        ``myList.add(``26``);``        ``myList.add(``3``);``        ``myList.add(``52``);``        ``myList.add(``70``);``        ``myList.add(``12``);`` ` ` ` `        ``// 'min' method is used to find the minimum element``        ``// from Collections Class``        ``System.out.println(``"Minimum Element in ArrayList = "``                           ``+ Collections.min(myList));``    ``}``}`
Output
`Minimum Element in ArrayList = 3`

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