LeetCode-Solution

Two Sum II - Input array is sorted

Description

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.

Tags:
Array

思路 1

javascript:

/**
 * @param {number[]} numbers
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(numbers, target) {
  let number = []
  for(let i = 0; i < Math.floor(numbers.length/2 + 1); i++) {
      if(numbers[i] <= target && numbers[i] !== numbers[i - 1] ) {
          let firstItem = target - numbers[i]
          let index = numbers.findIndex((item, j) => j!== i &&item === firstItem)
          if(index !== -1) {
              number.push(i + 1, index + 1)
              break
          }
      }
  }
  return number
};

结语

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