[LeetCode/JavaScript] 167. Two Sum II - Input array is sorted (easy)

 

문제 

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

Return the indices of the two numbers (1-indexed) as an integer array answer of size 2, where 1 <= answer[0] < answer[1] <= numbers.length.

The tests are generated such that there is exactly one solution. You may not use the same element twice.

 

 

입출력

Example 1:

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.

 

Example 2:

Input: numbers = [2,3,4], target = 6

Output: [1,3]

 

Example 3:

Input: numbers = [-1,0], target = -1

Output: [1,2]

 

 

제약

Constraints:

• 2 <= numbers.length <= 3 * 10^4
• -1000 <= numbers[i] <= 1000
• numbers is sorted in non-decreasing order.
• -1000 <= target <= 1000
• The tests are generated such that there is exactly one solution.

 

 

코드1

var twoSum = function(numbers, target) {
    for(let i=0; i<numbers.length-1; i++) {
        for(let j=i+1; j<numbers.length; j++) {
            if(numbers[i]+numbers[j] === target) return [i+1, j+1];
        }
    }
};

 

코드2

var twoSum = function(numbers, target) {
    for(let i=0; i<numbers.length-1; i++) {
        let answer = numbers.indexOf(target-numbers[i], i+1);
        if(answer!=-1) return [i+1, answer+1];
    }
};