题解 | 挑7

package main

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

func main() {
    var n int
    fmt.Scan(&n)
    count := 0
    for i :=1; i<=n; i++ {
        if i%7 ==0 || strings.Contains(strconv.Itoa(i), "7") {
            count++
        }
    }
    fmt.Println(count)

}