【ARC110】B - Many 110

• AtCoder
• ARC
• golang

AC

package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
)

var r = bufio.NewReader(os.Stdin)

func main() {
    fmt.Println(solve())
}

func solve() int {
    N := ni()
    T := ns()

    if N == 1 {
        switch T {
        case "1":
            return 2e10
        case "0":
            return 1e10
        default:
            return 0
        }
    }

    var f func(a, b string) bool

    f = strings.HasPrefix
    if f(T, "10") {
        T = "1" + T
    } else if f(T, "01") {
        T = "11" + T
    }

    f = strings.HasSuffix
    if f(T, "11") {
        T += "0"
    } else if f(T, "01") {
        T += "10"
    }

    if T == strings.Repeat("110", len(T)/3) {
        return 1e10 - len(T)/3 + 1
    }
    return 0
}

func ni() int    { var n int; fmt.Fscan(r, &n); return n }
func ns() string { var s string; fmt.Fscan(r, &s); return s }