Combination Sum

Given an array of distinct integers candidates and a target, return a list of all unique combinations where the chosen numbers sum to target.

Key Rule: The same number may be chosen from candidates an unlimited number of times.

This is a classic backtracking problem. At each step, we have choices:

1. Include the current candidate number again (and stay at same index i).
2. Skip the current candidate and move to the next (i + 1).

Pruning:

• If currentSum > target, stop (backtrack).
• If currentSum == target, add to result.

Visualize the decision making. Notice how we can branch 'left' multiple times (reusing same number) until it exceeds target.

Try clicking 'Randomize' to see how the tree changes with different targets and candidates.