Minesweeper Algorithm

Simple iterative solution to counts mines in Minesweeper

Usage

• Provide a 2D list of a rectangular board with -1 representing a mine and 0 in all other spaces
• call displayMines(board) passing in the board and the number of mines adjacent to each square will be printed preserving mines as -1
• Works for non-square dimensions

Algorithm

• Copies the board to a new board where the counts will reside
• Loops over all squares in the input board
• If a mine is encountered, it checks the 8 surrounding squares & increments the count in each square that isn't a mine
  • Surrounding squares are checked by a nested for loop, xTemp coordinates go from x-1 to x+1 & yTemp coordinates go from y-1 to y+1
  • All coordinates are checked to make sure they don't go out of bounds of the edges of the board
  • The current square is skipped by also checking if the value at board[ytemp]pxTemp] is a mine before incrementing

Runtime

O(mn) for looping over the entire board
O(8) for checking surrounding squares
O(8*mn) combined ⇒ O(mn)