这种情况为什么用array会比map快这么多呢

题目为leetcode 383题， https://leetcode.com/problems/ransom-note using map: 12ms, faster than 62.24% ``` func canConstruct(ransomNote string, magazine string) bool { m := make(map[rune] int, 0) for _, v := range magazine { m[v]++ } for _, v := range ransomNote { m[v]-- if m[v] < 0 { return false } } return true } ``` using array, 0ms faster than 100% ``` func canConstruct(ransomNote string, magazine string) bool { m := make([] int, 26) for _, v := range magazine { m[v - 'a']++ } for _, v := range ransomNote { m[v - 'a']-- if m[v - 'a'] < 0 { return false } } return true } ``` 使用这两种数据结构结果差这么多原因是什么呢，有大神可以科普下吗