go的，没有全部过，88%好像是 package main import ( "fmt" "strings" ) func main() { var s string fmt.Scan(&;s) s_t := strings.Split(s, "><") var stack []string for i := 0; i < len(s_t); i++ { if strings.HasPrefix(s_t[i], "<") { s_t[i] = s_t[i][1:] } else if strings.HasSuffix(s_t[i], ">") { s_t[i] = s_t[i][:len(s_t[i])-1] stack = append(stack) } else { stack = append(stack, s_t[i]) } } if len(s_t) == 1 { fmt.Println("NO") return } for i := 0; i < len(s_t); i++ { if strings.HasPrefix(s_t[i], "/") { if len(stack) == 0 { fmt.Println("NO") return } else if stack[len(stack)-1] != s_t[i][1:] { fmt.Println("NO") return } else if stack[len(stack)-1] == s_t[i][1:] { stack = stack[:len(stack)-1] } } else { stack = append(stack, s_t[i]) } } fmt.Println("YES") }