AlgoMotion
Quiz25
Two Pointers/Medium

3SumPRO PASS

Time: O(N^2)Space: O(1)

Initialize Two Pointers

Array is sorted. Set left pointer L=0 (val -4) and right pointer R=5 (val 2).

Array Elements & Pointers
L
-4
L
-1
[1]
-1
[2]
0
[3]
1
[4]
R
2
R
Live Variables & Invariants
target:0
left:0
right:5
sum:-2
Step 1 / 714%
Solution Code
1
function threeSum(nums: number[]): number[][] {
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  nums.sort((a, b) => a - b);
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  const res: number[][] = [];
4
  for (let i = 0; i < nums.length - 2; i++) {
5
    if (i > 0 && nums[i] === nums[i - 1]) continue;
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    let l = i + 1, r = nums.length - 1;
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    while (l < r) {
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      const sum = nums[i] + nums[l] + nums[r];
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      if (sum === 0) {
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        res.push([nums[i], nums[l], nums[r]]);
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        while (l < r && nums[l] === nums[l + 1]) l++;
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        while (l < r && nums[r] === nums[r - 1]) r--;
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        l++; r--;
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      } else if (sum < 0) l++;
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      else r--;
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    }
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  }
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  return res;
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}

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