1.two-sum.go

/*
 * @lc app=leetcode id=1 lang=golang
 *
 * [1] Two Sum
 *
 * https://leetcode.com/problems/two-sum/description/
 *
 * algorithms
 * Easy (40.14%)
 * Total Accepted:    1.4M
 * Total Submissions: 3.5M
 * Testcase Example:  '[2,7,11,15]\n9'
 *
 * Given an array of integers, return indices of the two numbers such that they
 * add up to a specific target.
 * 
 * You may assume that each input would have exactly one solution, and you may
 * not use the same element twice.
 * 
 * Example:
 * 
 * 
 * Given nums = [2, 7, 11, 15], target = 9,
 * 
 * Because nums[0] + nums[1] = 2 + 7 = 9,
 * return [0, 1].
 * 
 * 
 * 
 * 
 */
func twoSum(nums []int, target int) []int {
    m := make(map[int]int)
    for i := 0; i < len(nums); i++ {
        v := nums[i]

        if j, ok := m[target-v]; ok {
            return []int{j, i}
        }

        m[v] = i
    }

    return []int{}
}