Backtracking

How to avoid duplicates working with backtracking

One of the basic ideas for avoiding duplication involves sorting.

For example, we are given an array candidates = [10,1,2,7,6,1,5] and a target = 8.

How to find all unique combinations in candidates where the candidate numbers sum to target?

In here we have to avoid duplicates, for example, if we found [1,2,5] we have to avoid [2,1,5].

The solution is:

// sort an array
// inside the loop of the backtracking recursive function
if (i != start && array[i] == array[start]) {
    continue
}