Leetcode 1 Sum

Given an array of integers, find the numbers such that they add up to a specific target number.

The function twosum should return indices of the numbers such that they add up to the target, where index1 must is Les S than Index2. Please note that your returned answers (both Index1 and INDEX2) is not zero-based.

You may assume this each input would has exactly one solution.

Input:numbers={2, 7, one, A, target=9
Output:index1=1, index2=2

Use hash to store the array subscript for each value.

h = {A[index1] = index1, a[index2] = Index2, ...}

It takes two values to add up to sum, only to check if there is a key for the second value after sum minus the first value in the hash (the first value is obtained by traversing the array), and the two values are not the same number (corresponding to an array subscript for equality).

It is important to note that the last two number is the order in the sequence and should be subscript +1 for the array.

def two_sum (num, target)     = {}    num.length.times {|i| h[num[i]] = i}    num.length.times {returnif  and H[target-num[i]] > i}end

Leetcode 1 Sum