_167.java

package com.fishercoder.solutions;

/**
 * 167. Two Sum II - Input array is sorted

 Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.

 The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.

 Note:

 Your returned answers (both index1 and index2) are not zero-based.
 You may assume that each input would have exactly one solution and you may not use the same element twice.

 Example:

 Input: numbers = [2,7,11,15], target = 9
 Output: [1,2]
 Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.

 */

public class _167 {
    public static class Solution1 {
        public int[] twoSum(int[] numbers, int target) {
            int left = 0;
            int right = numbers.length - 1;
            while (left < right) {
                long sum = numbers[left] + numbers[right];
                if (sum > target) {
                    right--;
                } else if (sum < target) {
                    left++;
                } else {
                    int[] res = new int[2];
                    res[0] = left + 1;
                    res[1] = right + 1;
                    return res;
                }
            }
            return new int[] {-1, -1};
        }
    }
}