For problem statement at 1000-1999/1600-1699/1680-1689/1687/problemA.txt this is a correct solution, but verifier at 1000-1999/1600-1699/1680-1689/1687/verifierA.go ends with All tests passed can you fix the verifier? ```go
package main

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

type FastScanner struct {
	r *bufio.Reader
}

func NewFastScanner() *FastScanner {
	return &FastScanner{r: bufio.NewReader(os.Stdin)}
}

func (fs *FastScanner) nextInt64() int64 {
	sign := int64(1)
	val := int64(0)
	c, _ := fs.r.ReadByte()
	for (c < '0' || c > '9') && c != '-' {
		c, _ = fs.r.ReadByte()
	}
	if c == '-' {
		sign = -1
		c, _ = fs.r.ReadByte()
	}
	for c >= '0' && c <= '9' {
		val = val*10 + int64(c-'0')
		c, _ = fs.r.ReadByte()
	}
	return val * sign
}

func main() {
	in := NewFastScanner()
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	t := int(in.nextInt64())
	for ; t > 0; t-- {
		n64 := in.nextInt64()
		k := in.nextInt64()
		n := int(n64)

		a := make([]int64, n)
		for i := 0; i < n; i++ {
			a[i] = in.nextInt64()
		}

		pref := make([]int64, n+1)
		for i := 0; i < n; i++ {
			pref[i+1] = pref[i] + a[i]
		}
		sumAll := pref[n]

		if k <= int64(n) {
			L := int(k)
			var maxWin int64 = 0
			for i := 0; i+L <= n; i++ {
				s := pref[i+L] - pref[i]
				if s > maxWin {
					maxWin = s
				}
			}
			add := int64(L*(L-1)) / 2
			fmt.Fprintln(out, maxWin+add)
		} else {
			base := int64(n*(n-1)) / 2
			extra := (k - int64(n)) * int64(n)
			fmt.Fprintln(out, sumAll+base+extra)
		}
	}
}
```