Largest Element in an Array

Problem Statement

Given an array arr[], the task is to find and return the largest element in the array.

Example 1:

Input: arr[] = [1, 8, 7, 56, 90]

Output: 90

Explanation: The largest element in the array is 90.

Example 2:

Input: arr[] = [5, 5, 5, 5]

Output: 5

Explanation: All elements are equal, so the largest element is 5.

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Problem statement: Largest in Array | Practice | GeeksforGeeks

Approach

We can solve this problem by traversing the array and keeping track of the largest element found so far.

1. Initialize a variable largest with Integer.MIN_VALUE. This ensures that even if all array elements are negative, the algorithm works correctly.
2. Traverse the array using a for loop.
3. For each element, compare it with the current value of largest using the getMax() method.
4. Update largest with the greater value.
5. After traversing the entire array, return largest.

Java Solution

class Solution {

    public static int getMax(int a, int b) {
        if (a > b) {
            return a;
        } else {
            return b;
        }
    }
    public static int findLargest(int[] arr) {
        int largest = Integer.MIN_VALUE;
        for (int i = 0; i < arr.length; i++) {
            largest = getMax(arr[i], largest);
        }
      return largest;
    }
    public static int largest(int[] arr) {
        return findLargest(arr);
    }
}

Dry Run

Consider the input array:

arr[] = [1, 8, 7, 56, 90]

Initially, largest = Integer.MIN_VALUE.

ElementCurrent Largest11887856569090

After processing all the elements, the value of largest is 90, which is returned as the answer.

Complexity Analysis

Time Complexity: O(n)

The algorithm traverses the array exactly once, where n is the number of elements in the array. Each comparison takes constant time.

Space Complexity: O(1)

The algorithm uses only a constant amount of extra space for variables such as largest and i.

Conclusion

The largest element in an array can be found efficiently by traversing the array once and maintaining the maximum value encountered so far. The solution takes O(n) time and O(1) extra space, making it optimal for this problem.