Minimum distance in an Array

Problem Link - Minimum Distance

You are given an array a, of n elements. Find the minimum index based distance between two distinct elements of the array, x and y. Return -1, if either x or y does not exist in the array.

Examples:

Input: arr[] = {1, 2}, x = 1, y = 2
Output: Minimum distance between 1 and 2 is 1.
Input: arr[] = {3, 4, 5}, x = 3, y = 5
Output: Minimum distance between 3 and 5 is 2.
Input: arr[] = {3, 5, 4, 2, 6, 5, 6, 6, 5, 4, 8, 3}, x = 3, y = 6
Output: Minimum distance between 3 and 6 is 4.
Input: arr[] = {2, 5, 3, 5, 4, 4, 2, 3}, x = 3, y = 2
Output: Minimum distance between 3 and 2 is 1.

Approach

• Initialize two indices i1 and i2 to -1 to store the most recent indices of x and y found during the traversal of the array.
• Initialize a variable mini to a large value (e.g., INT_MAX) to keep track of the minimum distance.
• Traverse through the array and find the indices of x and y,if both were found then calculate the distance between them and update the mini variable.if again we found the x or y, then calcuate the distance with previously found x or y and update the mini variable.

Code

    int minDist(int a[], int n, int x, int y) {
        // code here
        int mini=INT_MAX;
        int i1=-1;
        int i2=-1;
        for(int i=0;i<n;i++){
            if(a[i]==x){
                i1=i;
            }
            else if(a[i]==y){
                i2=i;
            }
            if(i1!=-1&&i2!=-1){
                mini=min(mini,abs(i2-i1));
            }
        }
        if(i1==-1 || i2==-1){
            return -1;
        }
        return mini;
    }