huge-csv-1.go

package main

import (
	"bufio"
	"log"
	"os"
	"strconv"
	"strings"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	lastID := -1
	for scanner.Scan() {
		columns := strings.Split(scanner.Text(), ",")
		id, err := strconv.Atoi(columns[0])
		if err != nil {
			log.Fatalf("ParseInt: %v", err)
		}
		if id <= lastID {
			log.Fatal("😭")
		}
		lastID = id
	}
	if err := scanner.Err(); err != nil {
		log.Fatal("scanner: %v", err)
	}
	log.Println("👍")
}