algorithm - Finding out the minimum difference between elements in an array

Question

I have an integer array with some finite number of values. My job is to find the minimum difference between any two elements in the array.

Consider that the array contains

4, 9, 1, 32, 13

Here the difference is minimum between 4 and 1 and so answer is 3.

What should be the algorithm to approach this problem. Also, I don't know why but I feel that using trees, this problem can be solved relatively easier. Can that be done?

Answer 1

The minimum difference will be one of the differences from among the consecutive pairs in sorted order. Sort the array, and go through the pairs of adjacent numbers looking for the smallest difference:

int[] a = new int[] {4, 9, 1, 32, 13};
Arrays.sort(a);
int minDiff = a[1]-a[0];
for (int i = 2 ; i != a.length ; i++) {
    minDiff = Math.min(minDiff, a[i]-a[i-1]);
}
System.out.println(minDiff);

This prints 3.