For problem statement at 1000-1999/1900-1999/1980-1989/1985/problemH2.txt this is a correct solution, but verifier at 1000-1999/1900-1999/1980-1989/1985/verifierH2.go ends with test 11 failed
input:
1
4 4
..#.
..##
##.#
.#.#
expected:
12

got:
13

exit status 1 can you fix the verifier? package main

import (
	"bytes"
	"io"
	"os"
	"strconv"
)

type FastScanner struct {
	data []byte
	idx  int
	n    int
}

func NewFastScanner() *FastScanner {
	data, _ := io.ReadAll(os.Stdin)
	return &FastScanner{data: data, n: len(data)}
}

func (fs *FastScanner) skip() {
	for fs.idx < fs.n && fs.data[fs.idx] <= ' ' {
		fs.idx++
	}
}

func (fs *FastScanner) NextInt() int {
	fs.skip()
	val := 0
	for fs.idx < fs.n {
		b := fs.data[fs.idx]
		if b <= ' ' {
			break
		}
		val = val*10 + int(b-'0')
		fs.idx++
	}
	return val
}

func (fs *FastScanner) NextBytes() []byte {
	fs.skip()
	start := fs.idx
	for fs.idx < fs.n && fs.data[fs.idx] > ' ' {
		fs.idx++
	}
	return fs.data[start:fs.idx]
}

func main() {
	fs := NewFastScanner()
	t := fs.NextInt()
	var out bytes.Buffer

	for tc := 0; tc < t; tc++ {
		n := fs.NextInt()
		m := fs.NextInt()
		nm := n * m

		grid := make([]byte, nm)
		rowDots := make([]int, n)
		colDots := make([]int, m)

		for i := 0; i < n; i++ {
			s := fs.NextBytes()
			base := i * m
			copy(grid[base:base+m], s)
			for j := 0; j < m; j++ {
				if s[j] == '.' {
					rowDots[i]++
					colDots[j]++
				}
			}
		}

		rowDiff := make([]int, n+1)
		colDiff := make([]int, m+1)
		w := m + 1
		diff := make([]int, (n+1)*w)
		queue := make([]int, nm)

		for i := 0; i < n; i++ {
			base := i * m
			for j := 0; j < m; j++ {
				start := base + j
				if grid[start] != '#' {
					continue
				}

				grid[start] = '*'
				head, tail := 0, 1
				queue[0] = start

				size := 0
				minR, maxR := i, i
				minC, maxC := j, j

				for head < tail {
					p := queue[head]
					head++
					size++

					r := p / m
					c := p % m

					if r < minR {
						minR = r
					}
					if r > maxR {
						maxR = r
					}
					if c < minC {
						minC = c
					}
					if c > maxC {
						maxC = c
					}

					if r > 0 {
						q := p - m
						if grid[q] == '#' {
							grid[q] = '*'
							queue[tail] = q
							tail++
						}
					}
					if r+1 < n {
						q := p + m
						if grid[q] == '#' {
							grid[q] = '*'
							queue[tail] = q
							tail++
						}
					}
					if c > 0 {
						q := p - 1
						if grid[q] == '#' {
							grid[q] = '*'
							queue[tail] = q
							tail++
						}
					}
					if c+1 < m {
						q := p + 1
						if grid[q] == '#' {
							grid[q] = '*'
							queue[tail] = q
							tail++
						}
					}
				}

				r1 := minR - 1
				if r1 < 0 {
					r1 = 0
				}
				r2 := maxR + 1
				if r2 >= n {
					r2 = n - 1
				}
				c1 := minC - 1
				if c1 < 0 {
					c1 = 0
				}
				c2 := maxC + 1
				if c2 >= m {
					c2 = m - 1
				}

				rowDiff[r1] += size
				rowDiff[r2+1] -= size
				colDiff[c1] += size
				colDiff[c2+1] -= size

				diff[r1*w+c1] += size
				diff[(r2+1)*w+c1] -= size
				diff[r1*w+c2+1] -= size
				diff[(r2+1)*w+c2+1] += size
			}
		}

		rowSum := make([]int, n)
		cur := 0
		for i := 0; i < n; i++ {
			cur += rowDiff[i]
			rowSum[i] = cur
		}

		colSum := make([]int, m)
		cur = 0
		for j := 0; j < m; j++ {
			cur += colDiff[j]
			colSum[j] = cur
		}

		ans := 0
		for i := 0; i < n; i++ {
			rowBase := i * w
			prevRowBase := (i - 1) * w
			gridBase := i * m
			for j := 0; j < m; j++ {
				idx := rowBase + j
				v := diff[idx]
				if i > 0 {
					v += diff[prevRowBase+j]
				}
				if j > 0 {
					v += diff[rowBase+j-1]
				}
				if i > 0 && j > 0 {
					v -= diff[prevRowBase+j-1]
				}
				diff[idx] = v

				score := rowDots[i] + colDots[j]
				if grid[gridBase+j] == '.' {
					score--
				}
				score += rowSum[i] + colSum[j] - v

				if score > ans {
					ans = score
				}
			}
		}

		out.WriteString(strconv.Itoa(ans))
		if tc+1 < t {
			out.WriteByte('\n')
		}
	}

	os.Stdout.Write(out.Bytes())
}