Finding the second smallest integer in array

Question

We are required in our assignment to find the second smallest integer in one array recursively. However, for the sake of understanding the subject more, I want to do it iter

Answer 1

Simply, you can do this

int[] arr = new int[]{34, 45, 21, 12, 54, 67, 15};
Arrays.sort(arr);
System.out.println(arr[1]);

Answer 2

    int[] arr = { 4, 1, 2, 0, 6, 1, 2, 0 };

    int smallest = Integer.MAX_VALUE;
    int smaller = Integer.MAX_VALUE;
    int i = 0;

    if (arr.length > 2) {
        for (i = 0; i < arr.length; i++) {

            if (arr[i] < smallest) {
                smaller = smallest;
                smallest = arr[i];
            } else if (arr[i] < smaller && arr[i] > smallest) {
                smaller = arr[i];
            }
        }

        System.out.println("Smallest number is " + smallest);
        System.out.println("Smaller number is " + smaller);

    } else {
        System.out.println("Invalid array !");
    }
}

Answer 3

You can do it in O(n) time. Below is the python code

def second_small(A):
    if len(A)<2:
        print 'Invalid Array...'
        return
    small = A[0]
    second_small = [1]
    if small >  A[1]:
        second_small,small = A[0],A[1]

    for i in range(2,len(A)):
        if A[i] < second_small and A[i]!=small:
            if A[i] < small:
                second_small = small
                small = A[i]
            else:
                second_small = A[i]
    print small, second_small
A = [12, 13, 1, 10, 34, 1]
second_small(A)

Answer 4

public static int findSecondSmallest(int[] elements) {
    if (elements == null || elements.length < 2) {
        throw new IllegalArgumentException();
    } 
    int smallest = elements[0]; 
    int secondSmallest = elements[0]; 
    for (int i = 1; i < elements.length; i++) {
        if (elements[i] < smallest) {
            secondSmallest = smallest;
            smallest = elements[i];
        } 
        else if (elements[i] < secondSmallest) {
            secondSmallest = elements[i];
        }
    }
    return secondSmallest;
}

Answer 5

class A{
    public static void main (String args[]){
        int array[]= {-5, -4, 0, 2, 10, 3, -3};
        int min;
        int second_min;
        if(array[0]<array[1]){
            min=array[0];
            second_min=array[1];
        }else{
            min=array[1];
            second_min=array[0];
        }
        for(int i=2;i<array.length;i++){
            if(second_min > array[i] && min > array[i]){
                    second_min=min;
                    min=array[i];                              
            }else  if(second_min > array[i] && min < array[i]){
                min=min;
                second_min=array[i];
            }
        }
        System.out.println(min);
        System.out.println(second_min);
    }
}

Answer 6

public static int getSecondSmallest(int[] arr){
        int smallest = Integer.MAX_VALUE;
        int secondSmallest = Integer.MAX_VALUE;
        for(int i=0;i<arr.length;i++){
            if(smallest > arr[i]){
                secondSmallest = smallest;
                smallest = arr[i];
            }else if (secondSmallest > arr[i] && arr[i] != smallest){
            secondSmallest = arr[i];
        }
            System.out.println(i+" "+smallest+" "+secondSmallest);
        }
        return secondSmallest;
    }

Just gave it a try with some of the test cases and it worked. Please check if it is correct!