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167. Two Sum II - Input Array Is Sorted 👍

  • Time: $O(n)$
  • Space: $O(1)$
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class Solution {
 public:
  vector<int> twoSum(vector<int>& numbers, int target) {
    int l = 0;
    int r = numbers.size() - 1;

    while (numbers[l] + numbers[r] != target)
      if (numbers[l] + numbers[r] < target)
        ++l;
      else
        --r;

    return {l + 1, r + 1};
  }
};

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class Solution {
  public int[] twoSum(int[] numbers, int target) {
    int l = 0;
    int r = numbers.length - 1;

    while (numbers[l] + numbers[r] != target)
      if (numbers[l] + numbers[r] < target)
        ++l;
      else
        --r;

    return new int[] {l + 1, r + 1};
  }
}

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class Solution:
  def twoSum(self, numbers: list[int], target: int) -> list[int]:
    l = 0
    r = len(numbers) - 1

    while l < r:
      summ = numbers[l] + numbers[r]
      if summ == target:
        return [l + 1, r + 1]
      if summ < target:
        l += 1
      else:
        r -= 1