Coding Interview Problem - Combination Sum

Solutions and video explanation to the commonly asked coding interview question Combination Sum.

Timestamps:
Understanding the Problem: 0:00
Brute Force Recursive Solution: 1:16
Recursive with memoization: 8:42
Dynamic Programming: 12:30

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[lytung]

The explanation is perfect. It's a headache to understand it before, now it's clear to me. Thanks a lot!

[jw]

Your explanation is excellent. Helping me to understand the different approaches better... one little suggestion, you can create a short follow up video to expand this solution to output all the combinations, as it will then be the solution for Leetcode question 39 (or 216)

[Alex-tmhr]

Just a heads up - this is for LC Combination Sum IV.

[meht]

Is that possible for the above dynamic solution once we have dp populated than can we to read it to derive all combinations? For example, once we know target 5 can be built in 10 ways, can we read all 10 combinations using dp table alone?

[callmechocolateboy]

why didnt you used memo as hash map ??