[Grind 169] 1. Two Sum

Problem Link: https://leetcode.com/problems/two-sum/

Solution 1:

func twoSum(nums []int, target int) []int {
    var n = len(nums)
    for i := 0; i < n; i ++ {
        for j := i+1; j < n; j++ {
            if nums[i] + nums[j] == target {
                return []int{i, j}
            } 
        }
    }
    return []int{}
}

Solution 2:

func twoSum(nums []int, target int) []int {
    var data = make(map[int]int)
    for j, v := range nums {
        if i, ok := data[v]; ok {
            return []int{i, j}
        } else {
            data[target - v] = j
        }
    }
    return []int{}
}