3Sum - Leetcode 15 - 2 Pointers (Python)

The Python code for this problem can be found at my GitHub repo here: github.com/gahogg/Leetcode-So...
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[@abbasfadhil1715]

Naming the function three sum is wild ☠️

[@khndokarrashid2991]

Love your videos man! im currently a data analyst trying to transfer over to software engineering and this is helping me a lot!

[@GregHogg]

That's awesome! Glad to hear it and best of luck :)

[@ankitchoudhary4618]

Very informative 👍

[@siddheshdewalekar7364]

Nice info👍

[@newbiedb]

At 5:21, can you explain more about hashable and mutable in Set?

[@DariusD0815]

What is considered a "duplicate triplet"? All value permutations of a triplet are duplicates? e.g. [2,-1,-1] or [-1,2,-1]?

[@GregHogg]

Yeah different permutations of the same numbers are not desired

[@SashoSuper]

I like those videos.

[@GregHogg]

Awesome!

[@ThsHunt]

why do the step of filling hashset doesnt count towards the time

[@sonicrushXII]

It does take time, But it's constant time
Constants are generally dropped when Calculating end time

[@lakshayjain9337]

Great logic
But why this c++ code is storing similar strings
vector threeSum(vector& nums) {
unordered_map map;
int i,j,n=nums.size();
vector ans;
sort(nums.begin(),nums.end());
for(i=0;i

[@santanu_barua]

Java Solution for this:
-------------------------------------
public List threeSum(int[] nums) {
Map map = new HashMap();
for (int i = 0; i< nums.length; i++) {
map.put(nums[i], i);
}
Set result = new HashSet();
for (int i = 0; i< nums.length;i++) {
for (int j = i+1; j< nums.length; j++) {
int desired = -nums[i] - nums[j];
if (map.containsKey(desired) && map.get(desired)!= i && map.get(desired)!=j) {
List triplet = Arrays.asList(nums[i], nums[j], desired);
Collections.sort(triplet);
result.add(triplet);
}
}
}
return new ArrayList(result);
}

[@NitinKumar-qs9tw]

Hey Greg! unfortunately time limit exceeded for last test case [0,0,0,0,0.........0,0,0] on Leetcode. 312/313 test cases passed.

[@GregHogg]

Yeah, they added this test case in literally a few days after I posted this video. I'll have to redo it with the n^2 solution that avoids using a Hashmap

[@benravenhill484]

My brain exploded

[@GregHogg]

😂

[@rakeshande449]

It's getting TLE

[@GregHogg]

Yes, they actually changed it very recently and this no longer passes! You need to do the one where you sort and then use two pointers now

[@maestro.a]

thanks for answered. I got TLE too.@@GregHogg

[@jagrat12354]

getting Time Limit Exceeded using this method, dont know why. Even running ur code does the same

[@GregHogg]

They recently changed this question so this solution doesn't run on the last test case. Very dumb of them to do that

[@saaddude1]

@@GregHogg Any idea, how to tweak the solution to pass all test cases?

[@antipainK]

Using a set feels like cheating here...