前置き

Atcoderをやってみたので、自分用のメモです。
あとから加筆・修正する予定です。

問題

A

Q_A.go

package main

import (
    "fmt"
)

func main() {
    var A, B float32
    fmt.Scanf("%f %f", &A, &B)

    wariai := (A-B)/A *100

    fmt.Printf("%f\n", wariai)
}

B

Q_B.go

package main

import (
    "bufio"
    "fmt"
    "os"
    "strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
    sc.Scan()
    i, e := strconv.ParseInt(sc.Text(),10,32)
    if e != nil {
        panic(e)
    }
    return int(i)
}

func main() {

    sc.Split(bufio.ScanWords)

    var N int
    fmt.Scanf("%d",&N)

    var min_p int = -1

    var A, P, X int 
    for i:=0; i<N; i++{
        A = nextInt()
        P = nextInt()
        X = nextInt()

        if (A < X) && (min_p < 0){
            min_p = P
        } else if (A < X) && (P < min_p){
            min_p = P
        }
    }

    fmt.Printf("%d\n", min_p)
}

C

Q_C.go

package main

import (
    "fmt"
)

func main() {
    var N int64
    fmt.Scanf("%d", &N)

    var i, v int64

    m := make(map[int64]int)

    for i=2; i*i<=N; i++{
        v = i
        for j:=0; ; j++{
            v = v * i
            if v <= N{
                _, isThere := m[v]
                if !isThere {
                    m[v] = 1
                }
            } else {
                break
            }
        }
    }

    result := N - int64(len(m))

    fmt.Printf("%d\n", result)  
}

D

Q_D.go

package main

import (
    "fmt"
    "strings"
    "strconv"
)

func score(s []int) int{
    hand := make(map[int]int)
    for i:=0; i<5; i++{
        _, isThere := hand[s[i]]
        if !isThere {
            hand[s[i]] = 1
        } else {
            hand[s[i]] = hand[s[i]] + 1
        }         
    }

    var sc int = 0
    for i:=1; i<10; i++{
        _, isThere := hand[i]
        var r int = 1
        if isThere {
            for j:=0; j<hand[i]; j++{
                r = r * 10
            }
            sc += i * r
        }else {
            sc += i
        }
    }

    return sc
}

func prob(m map[int]int,K int, s int , t int) float64 {

    var p float64
    if s == t {
        bunshi := m[s]
        bunshi *= m[s] -1
        bunbo := (9*K-8) * (9*K-9) 
        p = float64(bunshi) / float64(bunbo) 
    } else {
        bunshi := m[s]
        bunshi *= m[t]
        bunbo := (9*K-8) * (9*K-9) 
        p = float64(bunshi) / float64(bunbo)
    }

    return p
}

func main() {
    var K int
    var S, T string

    fmt.Scanf("%d", &K)
    fmt.Scanf("%s", &S)
    fmt.Scanf("%s", &T)

    m := make(map[int]int)
    for i:=1; i<10; i++{
        m[i] = K
    }

    S_fact := strings.Split(S, "")
    T_fact := strings.Split(T, "")

    for i:=0; i<4; i++{
        n, _ := strconv.Atoi(S_fact[i])
        m[n] = m[n] - 1

        l, _ := strconv.Atoi(T_fact[i])
        m[l] = m[l] - 1
    }

    var result float64 = 0
    for i:=1; i<10; i++{
        for j:=1; j<10; j++{
            p := prob(m, K, i, j)
            var s []int
            for k:=0; k<4; k++{
                tmp, _ := strconv.Atoi(S_fact[k])
                s = append(s, tmp)
            }
            s = append(s, i)
            score_s := score(s)

            var t []int
            for k:=0; k<4; k++{
                tmp, _ := strconv.Atoi(T_fact[k])
                t = append(t, tmp)
            }
            t = append(t, j)
            score_t := score(t)

            if score_s > score_t {
                result += p
            }
        }
    }

    fmt.Printf("%f\n", result)
}

E

覚えてたら後で書きます。

F

覚えてたら後で書きます。

エラー

$ go get github.com/motemen/ghq
go get: github.com/motemen/ghq@v1.0.3 updating to
    github.com/motemen/ghq@v1.1.6: parsing go.mod:
    module declares its path as: github.com/x-motemen/ghq
            but was required as: github.com/motemen/ghq

解決策

$ go get github.com/x-motemen/ghq

なぜ

motemen さんが x-motemen さんに改名した？