Exercise: Maps

strings.Fields拆分单词，然后用map[string]int直接统计，主要代码：

1 func WordCount(s string) map[string]int {
2     fields := strings.Fields(s)
3     result := make(map[string]int)
4     for _, field := range fields {
5         result[field] += 1
6     }
7     return result
8 }