4SUM | Leetcode 18 | Live coding session

Here is the solution to "4Sum" leetcode question. Hope you have a great time going through it.

Chapters
1) 0:00 Explaining the problem out loud
2) 1:10 Question walkthrough
3) 2:30 Algorithm
5) 8:00 Coding it up

For discussion/feedback

PS : Please increase the speed to 1.25X

[FaizanKhan-gfaizank]

Beats 90% and works well for the newly added test cases as well....
class Solution {
public List<List<Integer>> fourSum(int[] nums, int target) {
List<List<Integer>> list=new ArrayList<>();

if(nums.length==4){
&& nums[1] !=
List<Integer> l = new ArrayList<>();
l.add(nums[0]);
l.add(nums[1]);
l.add(nums[2]);
l.add(nums[3]);
list.add(l);
return list;
}
if(nums[0] == || nums[0] ==
return list;
}
}

Arrays.sort(nums);
for(int i=0;i<nums.length-3;i++){
if(i!=0 && nums[i]==nums[i-1])continue;

for(int j=i+1;j<nums.length-1;j++){
if(j!=i+1 && nums[j]==nums[j-1])continue;

int left=j+1, right=nums.length-1;
while(left<right){
int
if(sum<target) left++;
else if(sum>target) right--;
else{
List<Integer> combs=new ArrayList<>();
combs.add(nums[i]);
combs.add(nums[j]);
combs.add(nums[left]);
combs.add(nums[right]);

list.add(combs);

left++;
right--;

while(left<right &&
while(left<right &&
}
}
}
}
return list;
}
}

[focminging]

Passing all test cases of this problem is more satisfying than having an actual foursome. Thanks.

[mdpearehabib]

Leetcode added new test case for overflow..this code doesn't work...it will fail test case 283

[vigneshmanoharan]

Good explanation bro... I have started learning DSA deeply for a month but couldn't solve any problems on own... Do we need to practice more to solve problems of our own?

[santoshvarma]

can you please explain how this code will work for
arr: 1, 1, 1, 1
target=4

[anshumanshukla]

Amazing explanation but if array:
and target: -294967296
this isn't going to run...