LeetCode101: 167. Two Sum II - Input Array Is Sorted

April 7, 2022 · 1 min · Gray King

tags: LeetCode101,Sorting,Two Pointers

Key ideas:

Move both sides to inwards.
If the sum value less than target, move left pointer.
Otherwise move right poinger.

class Solution {
public:
	vector<int> twoSum(vector<int>& numbers, int target) {
		int S, l = 0, r = numbers.size() - 1;
		vector<int> res(2, 0);

		while (l < r) {
			S = numbers[l] + numbers[r];
			if (S == target) {
				break;
			}
			if (S < target) {
				l++;
			} else {
				r--;
			}
		}
		res[0] = l + 1;
		res[1] = r + 1;
		return res;
	}
};

Links to this note

LeetCode101: 18. 4Sum

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LeetCode101: 15. 3Sum

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