lecture8 - OOP and recursion

The algorithm keeps moving down paths until it hits a

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The algorithm keeps  moving down paths  until it hits a  dead end .   Once it hits a dead end, the function returns until there is an unvisited adjacent  square and tries another path.

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Solving a Maze void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } bool solvable; // globals int dx, dy; char maze[11][11] = { "**********", "* *", "* * * ** *", "*** * * *", "* * ** * *", "* *** *", "* * * *", "* ***** *", "* * *", "**********“ }; main() { solvable = false ; dx = dy = 10; solve( 1 , 1 ); if (solvable == true) cout << “possible!” };   Finish # Start 1 1 void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } 2 1 # 1 == 10 && 1 == 10?? // dead end! 1 == 10 && 2 == 10??
Solving a Maze void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } bool solvable; // globals int dx, dy; char maze[11][11] = { "**********", "* *", "* * * ** *", "*** * * *", "* * ** * *", "* *** *", "* * * *", "* ***** *", "* * *", "**********“ }; main() { solvable = false ; dx = dy = 10; solve( 1 , 1 ); if (solvable == true) cout << “possible!” };   Finish # Start # 1 1 void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } 1 2 # 2 == 10 && 1 == 10?? void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } 1 3 # 3 == 10 && 1 == 10?? void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } 2 3 # And on it goes…

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Solving a Maze void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } bool solvable; // globals int dx, dy; char maze[11][11] = { "**********", "* *", "* * * ** *", "*** * * *", "* * ** * *", "* *** *", "* * * *", "* ***** *", "* * *", "**********“ }; main() { solvable = false ; dx = dy = 10; solve( 1 , 1 ); if (solvable == true) cout << “possible!” };   Finish # Start # 1 1 void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } # 2 == 10 && 1 == 10?? void solve(int sx, int sy) { m[sy][sx] = ‘#’; // drop crumb if (sx == dx && sy == dy) solveable = true; // done! if (m[sy-1][sx] == ' ‘) solve(sx,sy-1); if (m[sy+1][sx] == ' ‘) solve(sx,sy+1); if (m[sy][sx-1] == ' ‘) solve(sx-1,sy); if (m[sy][sx+1] == ' ‘) solve(sx+1,sy); } # 3 == 10 && 1 == 10??
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