public class TwoSumII { public static int[] twoSum(int[] nums, int target) { if (nums == null || nums.length < 2) { throw new IllegalArgumentException("No two sum solution"); } int l = 0, r = nums.length - 1; while (l < r) { int sum = nums[l] + nums[r]; if (sum < target) { l++; } else if (sum > target) { r--; } else { return new int[] {l + 1, r + 1}; } } throw new IllegalArgumentException("No two sum solution"); } }