Generating Minesweeper grids

Question

Minesweeper is a logic game found on most OS's. The goal of the game is to determine where the mines are on a grid, given numbers indicating the number of mines around that spot.

Given a grid size, and a set of mines, generate the Minesweeper grid for that set of mines.

Input: Two integers indicating the grid size, and an undefined number of integers indicating the mine positions. Positions will be given as (column position, row position), and the indexes will start at row 1.

Output: The Minesweeper grid. If there are no mines around a block, print an x. For each new row, print a newline. Please output all mines as an asterisk *. Do not leave any whitespace between the values in the row when printing.

Test Cases:

Input "5 5 1 3 3 5 2 4":

xxxxx
11xxx
*21xx
2*21x
12*1x

Input "3 4 3 1 1 4 2 3 3 2":

x2*
13*
2*2
*21

Shortest code wins.

Answer 1

GolfScript 122 98 94 93 91 88 87 85 82 81 80 71

~]2/(\:m;~\:w*,{[.w%)\w/)]:^m\?)42{m{^*~-.*@@-.*+3<},,72or 48+}if}%w/n*

Online demos:

Test Case 1: link

Test Case 2: link

Answer 2

J, 124 116 112 101 87 86 85 84 83 82 79 76 75 72 68 characters

'0x'charsub|:1":3 3(+/@,+9*4&{@,);._3[1(}.x)}0$~2+>{.x=._2<\".1!:1[1

Found what I was looking for - a way to get rid of the spaces (1":) - and finally I'm competitive. Now I just need to figure out the empty set of mines problem.

Takes input from the keyboard.

Edit

New version makes use of a side effect of 1": - numbers larger than 9 are replaced by *.

Answer 3

Mathematica - 247 chars

s[q_] :=
  Module[{d, r},
    d = ToExpression@Partition[Cases[Characters@q, Except@" "], 2];
    r = Rest@d;
    StringJoin @@@ 
    ReplacePart[
    Table[ToString@
       Count[ChessboardDistance[{i, j}, #] & /@ Reverse /@ r, 1], {i,d[[1, 2]]}, 
       {j, d[[1, 1]]}] /. {"0" -> "x"}, # -> "*" & /@ Reverse /@ r] // TableForm]

Examples:

s@"5 5 1 3 3 5 2 4"
s@"3 4 3 1 1 4 2 3 3 2"

Output:

ChessboardDistance computes how far each cell is from a mine, where 1 corresponds to "next to a mine". The Count of 1's yields the cell's number. Then mines (*) are inserted into array.

Answer 4

Mathematica, 140 139 137

Grid[(ListConvolve[BoxMatrix@1,#,2,0]/. 0->x)(1-#)/. 0->"*"]&@Transpose@SparseArray[{##2}->1,#]&@@#~Partition~2&@@#~ImportString~"Table"&

Writing that in a more readable form:

"5 5 1 3 3 5 2 4"

ImportString[%, "Table"][[1]] ~Partition~ 2

Transpose @ SparseArray[{##2} -> 1, #]& @@ %

ListConvolve[BoxMatrix@1, %, 2, 0]

(% /. 0 -> x) (1 - %%) /. 0 -> "*" // Grid

Answer 5

Python, 192 182 180 chars

I could save some if the input was comma-separated. Then the first line would be d=input() and the length 171 chars.
Having the mine coordinates 0-based rather than 1-based would also help. It cost me 8 chars to overcome.

d=map(int,raw_input().split())
m=zip(d[2::2],d[3::2])
for y in range(d[1]):print"".join((str(sum(abs(a-x-1)|abs(b-y-1)<2for a,b in m)or'x')+'*')[(x+1,y+1)in m]for x in range(d[0]))

Ungolfed version:

d=map(int,raw_input().split()) # Read whitespace terminated numbers into a list of numbers xsize,ysize = d[:2] # The first two numbers are the board size mines=zip(d[2::2],d[3::2]) # Convert items 3,4,5,6... to pairs (3,4),(5,6) representine mine coordinates

def dist(point,mine):                   # Distance between point (0-based coordinates) and mine (1-based coordinates)
    dx = abs(mine[0]-(point[0]+1))
    dy = abs(mine[1]-(point[1]+1))
    return dx | dy                      # Should be max(dx,dy), but this is close enough. Wrong for d>=2, but returns >=2 in this case.

for y in range(ysize):                  # Print lines one by one
    line_chars = [
        (str(
            sum(dist((x,y),(a,b))<2 for a,b in mines)   # Number of neighboring mines
            or 'x'                                  # 'x' instead of 0
        )
        +'*')                                       # For a single neighbor, we get "1*"
        [(x+1,y+1)in mines]                         # If a mine, get the '*', else the neighbor number
        for x in range(xsize)
    ]
    print "".join(line_chars)

Answer 6

Scala - 280 chars

val n=readLine split" "map{_.toInt}
val b=Array.fill(n(1),n(0))(0)
n drop 2 sliding(2,2)foreach{case Array(x,y)=>b(y-1)(x-1)=9
for{i<-(x-2 max 0)to(x min n(0)-1);j<-(y-2 max 0)to(y min n(1)-1)}b(j)(i)+=1}
b.map{r=>println(r.map{case 0=>"x"case x if x>8=>"*"case x=>""+x}mkString)}

Answer 7

VBA - 298 chars

Sub m(x,y,ParamArray a())
On Error Resume Next:ReDim b(x,y):For i=0 To (UBound(a)-1) Step 2:c=a(i):d=a(i+1):b(c,d)="*":For e=c-1 To c+1:For f=d-1 To d+1:v=b(e,f):If v<>"*" Then b(e,f)=v+1
Next:Next:Next:For f=1 To y:For e=1 To x:v=b(e,f):s=s & IIf(v<>"",v,"x")
Next:s=s & vbCr:Next:MsgBox s
End Sub

Skipping over errors with On Error Resume Next saved me some characters, but this still isn't nearly as good as some of the other answers. :-/

Answer 8

This is the beginning of a Brinfuck solution. It should be pretty readable with indention and stack comments (@ indicates the stack pointer):

>>,>,  |0|x|@y| Pop the first two characters
[>>+<<-]>>  |0|x|0|0|@y|
[<<+>+>-]<  |0|x|@y|y|0|
[  |0|x|y|@y|
  [>>+<<-]< |0|x|@y|0|0|y|
  [>>+<<-]< |0|@x|0|0|y|y|
  [>>+<<-]>> |0|0|0|@x|y|y|
  [<<+>+>-]<<  |0|@x|x|0|y|y|
  [>>+<<-]> |0|0|@x|x|y|y|
  [<< |@0|0|x|x|y|y|
    ++++++++[>+++++++++++<-]>>>>> |0|88|x|x|@y|y|
    [>+<-]< [>+<-]< [>+<-]< [>+<-]< |0|@88|0|x|x|y|y|
    [<+>-]>>-  |88|0|0|@x_1|x|y|y|
  ]<< |x x's|@0|0|0|x|y|y|
  ++++++++++>>> x's|\n|0|0|@x|y|y|
  [<+>-]>  x's|\n|0|x|0|@y|y|
  [<+>-]>  x's|\n|0|x|y|0|@y|
  [<+>-]<- |x 88s|0|x|@y_1|y|
] |@x 88s|0|x|y|

It is however far from complete and I am starting to doubt if my approach is optimal. So far it only considers the first two input characters and prints a table of Xs. For instance "43" would give you:

XXXX
XXXX
XXXX

I would love to see if somebody else has what it takes and is capable of solving this problem in Brainfuck.

Answer 9

C++ - 454 chars

This is worse than my VBA answer, which probably means I don't know what I'm doing in C++. However, I am trying to build on what I know of C++, so here it is. If anyone has any suggestions for improvement, I'd be grateful to hear them!

#define Z for(int i=
#define Y for(int j=
#define X d[i][j]
#define W Z 0;i<x;i++){
#define V Y 0;j<y;j++){
#define U cout<<
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
int main(){using namespace std;int x,y,a,b;cin>>y>>x;string c[x][y];int d[x][y];W V X=0;}}while(cin>>b>>a){c[--a][--b]="*";Z a-1;i<=a+1;i++){Y b-1;j<=b+1;j++){if(x>i&&i>=0&&y>j&&j>=0){X=X+1;}}}}W V if(c[i][j]!="*"){if(X>0){U X;}else{U"x";}}else{U"*";}}U endl;}return 0;}

Answer 10

C# (691 Chars)

using System;namespace M{class P{static char C(char[][] g,int r,int c){int n=0;for(int i=r-1;i<=r+1;i++){if(i<0||i>=g.Length)continue;for(int j=c-1;j<=c+1;j++){if((j<0||j>=g[0].Length)||(i==r&&j==c))continue;if(g[i][j]=='*')n++;}}return n==0?'x':(char)(n+48);}static char[][] G(int[] p){char[][] r=new char[p[1]][];for(int i=0;i<r.Length;i++)r[i]=new char[p[0]];for(int i=2;i<p.Length;){r[p[i+1]-1][p[i]-1]='*';i+=2;}for(int i=0;i<r.Length;i++)for(int j=0; j<r[0].Length;j++)if(r[i][j]!='*')r[i][j]=C(r,i,j);for(int i=0;i<r.Length;i++){for(int j=0;j<r[0].Length;j++)Console.Write(r[i][j]);Console.WriteLine();}return r;}static void Main(string[] args){G(new int[]{3,4,3,1,1,4,2,3,3,2});}}}

Non-golfed Version:

using System;
namespace M
{
    class P
    {
        static char C(char[][] g, int r, int c)
        {
            int n = 0;
            for (int i = r - 1; i <= r + 1; i++)
            {
                if (i < 0 || i >= g.Length) continue;
                for (int j = c - 1; j <= c + 1; j++)
                {
                    if ((j < 0 || j >= g[0].Length) || (i == r && j == c)) continue;
                    if (g[i][j] == '*') n++;
                }
            }
            return n == 0 ? 'x' : (char)(n + 48);
        }

        static char[][] G(int[] p)
        {
            char[][] r = new char[p[1]][];
            for (int i = 0; i < r.Length; i++)
                r[i] = new char[p[0]];
            for (int i = 2; i < p.Length; )
            {
                r[p[i + 1] - 1][p[i] - 1] = '*';
                i += 2;
            }
            for (int i = 0; i < r.Length; i++)
                for (int j = 0; j < r[0].Length; j++)
                    if (r[i][j] != '*') r[i][j] = C(r, i, j);
            for (int i = 0; i < r.Length; i++)
            {
                for (int j = 0; j < r[0].Length; j++)
                    Console.Write(r[i][j]);
                Console.WriteLine();
            } return r;
        } 
        static void Main(string[] args) 
        { 
            G(new int[] { 3, 4, 3, 1, 1, 4, 2, 3, 3, 2 }); 
        }
    }
}

Answer 11

K, 175

f:{g::(y;x)#(x*y)#"x";{.[`g;x;:;"*"]}@'-1+|:'(_(#z)%2;2)#z;{if[~"0"~z;$["x"=g .(x;y);.[`g;(x;y);:;z];]]}.'i,'$s:+/'{"*"=g . x}''{,/((x-1)+!3),\:/:(y-1)+!3}.'i:,/(!x),\:/:!y;g}

.

k)f[5;5;1 3 3 5 2 4]
"xxxxx"
"11xxx"
"*21xx"
"2*21x"
"12*1x"
k)f[3;4;3 1 1 4 2 3 3 2]
"x2*"
"13*"
"2*2"
"*21"