95 lines
2.0 KiB
Go
95 lines
2.0 KiB
Go
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// For more tutorials: https://blog.learngoprogramming.com
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//
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// Copyright © 2018 Inanc Gumus
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// Learn Go Programming Course
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// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
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//
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package main
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import (
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"bufio"
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"fmt"
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"os"
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"sort"
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"strconv"
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"strings"
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)
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// result stores the parsed result for a domain
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type result struct {
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domain string
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visits int
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// add more metrics if needed
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}
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// parser keep tracks of the parsing
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type parser struct {
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sum map[string]result // metrics per domain
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domains []string // unique domain names
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total int // total visits for all domains
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lines int // number of parsed lines (for the error messages)
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}
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func main() {
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p := parser{sum: make(map[string]result)}
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// Scan the standard-in line by line
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in := bufio.NewScanner(os.Stdin)
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for in.Scan() {
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p.lines++
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// Parse the fields
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fields := strings.Fields(in.Text())
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if len(fields) != 2 {
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fmt.Printf("wrong input: %v (line #%d)\n", fields, p.lines)
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return
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}
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domain := fields[0]
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// Sum the total visits per domain
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visits, err := strconv.Atoi(fields[1])
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if visits < 0 || err != nil {
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fmt.Printf("wrong input: %q (line #%d)\n", fields[1], p.lines)
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return
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}
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// Collect the unique domains
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if _, ok := p.sum[domain]; !ok {
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p.domains = append(p.domains, domain)
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}
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// Keep track of total and per domain visits
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p.total += visits
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// You cannot assign to composite values
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// p.sum[domain].visits += visits
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// create and assign a new copy of `visit`
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p.sum[domain] = result{
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domain: domain,
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visits: visits + p.sum[domain].visits,
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}
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}
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// Print the visits per domain
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sort.Strings(p.domains)
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fmt.Printf("%-30s %10s\n", "DOMAIN", "VISITS")
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fmt.Println(strings.Repeat("-", 45))
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for _, domain := range p.domains {
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parsed := p.sum[domain]
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fmt.Printf("%-30s %10d\n", domain, parsed.visits)
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}
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// Print the total visits for all domains
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fmt.Printf("\n%-30s %10d\n", "TOTAL", p.total)
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// Let's handle the error
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if err := in.Err(); err != nil {
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fmt.Println("> Err:", err)
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}
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}
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