题解 | #DNA序列#

package main

import (
    "fmt"
)

func calculateGC(s string) int {
    var cnt int
    
    for i:=0; i<len(s); i++ {
        if s[i] == 'G' || s[i] == 'C' {
            cnt++
        } 
    }

    return cnt
}

func findLongestStr(s string, k int) string {
    size := len(s)
    var maxCountGC int
    var longSubStr string

    for i:=0; i<=size-k; i++ {
        countGC := calculateGC(s[i:i+k])
        if countGC > maxCountGC {
            longSubStr = s[i:i+k]
            maxCountGC = countGC
        }
    }  

    return longSubStr
}

func main() {
    var s string
    var k int
    fmt.Scan(&s, &k)

    fmt.Println(findLongestStr(s, k))
}

// 本题输入为一个整数和一个字符串，所以采用：fmt.Scan(&s, &k)