Recover Sorted Array

Given a sorted array. Two elements are swapped. Recover this array.

Solution. Think about the case1:

Original array = [1, 2, 3, 4, 5, 6, 7].

Swapped array = [1, 7, 3, 4, 5, 6, 2].

And we have first and second with Integer type. In this way, we know
If arr[i] > arr[i + 1] and first == null, we have first = i.
If arr[i] > arr[i + 1] and first != null, we have second = i + 1

Another exception case happens when the swapped element are together:

Original array = [1, 2, 3, 4, 5, 6, 7].

Swapped array = [1, 3, 2, 4, 5, 6, 7].

In this way,
If arr[i] > arr[i + 1] and first == null, we have first = i, second = i + 1

Considering above 2 cases, below is a concise code for it:

public static void recoverArray(int[] arr) {
    Integer first = null, second = null;
    for (int i = 0; i < arr.length - 1; i++) {
        if (arr[i] > arr[i + 1]) {
            if (first == null) {
                first = i;
            }
            second = i + 1;
        }
    }
    int tmp = arr[first];
    arr[first] = arr[second];
    arr[second] = tmp;
}

Check my code on github.