[Jianzhi offer] 57 And are two numbers of S

The finger of the sword Offer 57. And for s Two numbers of

subject

Enter an ascending array and a number s, Find two numbers in an array , So that their sum is exactly s. If the sum of many pairs of numbers is equal to s, Then output any pair .

Ideas

• Double pointer , Set the pointer i,j Point to respectively nums The left and right ends of the array
• Calculation s = target[i] + target[j]
• If s > target So the pointer j Move to the left j = j - 1
• If s < target So the pointer i To the right i = i + 1
• s = target Return the array directly [nums[i],nums[j]]

Code

class Solution {
    
    public int[] twoSum(int[] nums, int target) {
    
        int i = 0,j = nums.length - 1;

        while(i < j)
        {
    
            int s = nums[i] + nums[j];
            if(s < target)
            {
    
                i++;
            }
            else if(s > target)
            {
    
                j--;
            }
            else{
    
                return new int[] {
    nums[i],nums[j]};
            }
        }

        return new int[0];
    }
}