Place N Queens on a NxN chessboard, with Go!

n-queens.go

func totalNQueens(n int) int {
    if n == 1 {
        return 1
    }
    
    board := make([][]bool, n)
    
    for i:=0;i<n;i++ {
        board[i] = make([]bool, n)
    }
    
    count := 0
    
    for i:=0;i<n;i++ {
        placeQueen(0, i, &count, &board)
        removeQueen(0, i, &board)
    }
    
    return count
}

func removeQueen(row, col int, board *[][]bool) {
    (*board)[row][col] = false
}

func placeQueen(row, col int, count *int, board *[][]bool) {
    (*board)[row][col] = true
  
    // uncomment if you want to see how the board builds
    // p(*board)
    for _, x := range available(row + 1, board) {
        if row + 1 == len(*board) - 1 {
            *count += 1
            // no need to place queens on last row but every slot counts 
            // as a final solution
            
            // remove this "continue" if you want to also log the last row filled with the last queen
            continue
        }
        placeQueen(row + 1, x, count, board)
        removeQueen(row + 1, x, board)
    }
}

func available(row int, board *[][]bool) (ret []int) {
    // move through the line --->
    for i:=0;i<len(*board);i++ {
        valid := true
        // then looping the rows
        for y:=0;y<row;y++ {
            // left diagonal
            left := i - (row - y)
            if left >= 0 {
                if (*board)[y][left] {
                    valid = false
                    break
                }
            }
            
            // right diagonal
            right := i + (row - y)
            if right < len(*board) {
                if (*board)[y][right] {
                    valid = false
                    break
                }
            }
            
            // column
            if (*board)[y][i] {
                valid = false
                break
            }
        }
        // 
        if !valid {
            continue
        }
        //
        ret = append(ret, i)
    }
    return
}

func p(matrix[][]bool) {
    fmt.Println("----------")
    for _, row := range matrix {
        line := "| "
        for _, c := range row {
            if c {
                line += " X "
            } else {
                line += " O "
            }
            line += " | "
        }
        fmt.Println(line)
    }
    fmt.Println("----------")
}