CODEWITHSUNDEEP
javaarrays
Nauruto
Nauruto

Reputation: 153

Find the index of two minimum values in array

I have an array that contains numbers.

I got the two minimum values (can be the same number) of this array in O(N) but i cant figure out how to get the index of this two values.

For example: in {1,2,3,1,5} the answer will be index 0 and index 3. this is the code i'm using:

    public static void minMin(int arr[]){
    int min1 = weights[0], min2 = weights[1];
      if(min1 > min2){
       int temp = min1;
       min1 = min2;
       min2 = temp;
      }
      for (int i = 2; i < weights.length; i++) {
       if(weights[i] < min1){
        int temp = min1;
        min1 = weights[i];
        min2 = temp;
       }else if(weights[i] < min2){
        min2 = weights[i];
       }
      }
}

Upvotes: 0

Views: 1066

Answers (2)

GhostCat
GhostCat

Reputation: 140613

In addition to the local variables that keep the minimum values you need variables for the indexes, too.

You initiatilaze them with 0/1 and update them whenever you change the other variables.

Further thinking about this: one other option works without more variables. Storing value + index is convenient (the comment is correct though, you would probably use a distinct class to do that) but not mandatory. Because you can always fetch the value when you have an index!

In that sense: you could change your code to remember indixes only.

Upvotes: 5

Dennux
Dennux

Reputation: 240

Ghostcat already gave the answer, you just didnt understand:

I have only one index because its one for loop and i need the index's of two elements..

Just create more variables:

public static void main(String[] args) {

    minMin(new int[] { 1, 2, 3, 1, 5 });
}

// Careful: this code only works for arr.lengh > 1
public static void minMin(int arr[]) {

    int min1 = arr[0];
    int min2 = arr[1];

    int index1 = 0;
    int index2 = 1;

    if (min1 > min2) {
        int temp = min1;
        min1 = min2;
        min2 = temp;

        index1 = 1;
        index2 = 0;
    }

    for (int i = 2; i < arr.length; i++) {
        if (arr[i] < min1) {
            int temp = min1;
            min1 = arr[i];
            min2 = temp;
            index2 = index1;
            index1 = i;
        } else if (arr[i] < min2) {
            min2 = arr[i];
            index2 = i;
        }
    }

    System.out.println("Smallest: " + min1 + ", index " + index1);
    System.out.println("2nd smallest: " + min2 + ", index " + index2);
}

Output:

Smallest: 1, index 0
2nd smallest: 1, index 3

Upvotes: 1

Related Questions