day-28.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"sort"
	"strconv"
	"strings"
)

func main() {
	reader := bufio.NewReaderSize(os.Stdin, 16*1024*1024)

	NTemp, err := strconv.ParseInt(strings.TrimSpace(readLine(reader)), 10, 64)
	checkError(err)
	N := int32(NTemp)

	var names []string
	for NItr := 0; NItr < int(N); NItr++ {
		firstMultipleInput := strings.Split(strings.TrimSpace(readLine(reader)), " ")

		firstName := firstMultipleInput[0]

		emailID := firstMultipleInput[1]
		i := 0
		n := len(emailID)
		for i < n && emailID[i] != '@' {
			i++
		}

		if i+6 < n && emailID[i+1:i+6] == "gmail" && i+10 <= n && emailID[i+7:i+10] == "com" {
			names = append(names, firstName)
		}
	}
	sort.Strings(names)
	for i := 0; i < len(names); i++ {
		fmt.Println(names[i])
	}
}

func readLine(reader *bufio.Reader) string {
	str, _, err := reader.ReadLine()
	if err == io.EOF {
		return ""
	}

	return strings.TrimRight(string(str), "\r\n")
}

func checkError(err error) {
	if err != nil {
		panic(err)
	}
}