Combination Sum III | Leetcode | Medium | Java | Recursion | Striver's A to Z DSA Sheet

Combination sum III is a famous question and is frequently asked in interviews. This can be easily solved using recursion by Pick and Not-pick technique but you need a little familiarity with recursion if you want to solve this on your own.

Other problems for practice on leetcode:

[UjjwalMishra-sccl]

Nice explanation. The best part about your explanations are you demostrate through dry run and then provide simple solutions.

[arnabsarkar]

Hello didi, i was trying this question. My code is slightly different from you.

class Solution {
List<List<Integer>> ans = new ArrayList<>();
List<Integer> res = new ArrayList<>();

public List<List<Integer>> combinationSum3(int k, int n) {
// helper(1, k, n);
helper2(1, k, n, 0);
return ans;
}

public void helper2(int i, int size, int target, int sum) {
if (i > 9) {
return;
}

if (sum == target && res.size() == size) {
ans.add(new ArrayList<>(res));
return;
}

sum += i;
res.add(i);
helper2(i + 1, size, target, sum);

sum -= i;
res.remove(res.size() - 1);
helper2(i + 1, size, target, sum);
}
}

Can you please tell my why it is failing for the case (9, 45)

[kanpuriya_engineer]

To the point explanation, loved it >>💖

[letscrackthecodewithshweta]

Keep posting such videos❤ I love your channel and the solution you providing💯

[shi-]

Amazing Explanation, keep doing the same work!

[Shauryacious]

didi put abit more effort in sudo code and algo
and then again dry run the code.... cuz beginners like me will love to watch and help you grow