Using C # to develop smartphone software: Push Box (iv)

In the article "using C # to develop smartphone software: Push box (c)", I made a general introduction to the Push box program. In this article, the Common/findpath.cs source program file is introduced.

The following is a reference fragment:

using System;


using System.Drawing;


using System.Collections.Generic;


namespace Skyiv.Ben.PushBox.Common


{


///


///to find the shortest route


///


Static Class Findpath


{


static size[] offsets = {New Size (0, 1), New size (1, 0), new size (0,-1), New size (-1, 0)};


static direction[] Directions = {Direction.south, direction.east, Direction.north, direction.west};


///


///to find the shortest route


///


///Map


///starting point


///Destination


///Shortest Route


public static Queue Seek (ushort[,] map, point from, point to)


{


Queue movequeue = new Queue (); Route


int value; Distance from Destination


if (Seek (map, to, out value))//found a route


{


point here = from; Starting point (i.e. the position of the worker)


point NBR = new Point (); Four-week neighbor
.

for (value--value > 0; value--)//step towards destination


{


for (int i = 0; i < offsets. Length; i++)


{


NBR = Fcl.add (here, offsets[i]); Start looking around for neighbors


if (Block.value MAP[NBR. Y, NBR. X] = = value)//Just go in this direction


{


Movequeue.enqueue (Directions[i]); The route extends to the destination


break;


}


}


here = NBR; Keep moving,
.

}


}


Block.cleanallmark (map); Clear all signs, restore the scene


return movequeue; The route being sought, if the destination is not reached, the length of the route is zero


}


///


///Find the shortest route, use breadth First search


///


///Map


///Destination


///Output: Length of route (plus 1)


///is successful


static bool Seek (ushort[,] map, point to, out int value)


{


Queue q = new Queue ();


Block.mark (ref map[to. Y, to. X], 1); Start looking back from your destination and mark your destination as 1


point NBR = Point.empty; Four-week neighbor
.

for (;;)


{


value = Block.value (map[to. Y, to. X]) + 1; Distance from destination (plus 1), used as marker


for (int i = 0; i < offsets. Length; i++)


{


NBR = Fcl.add (To, offsets[i]); Start looking around for neighbors


if (Block.isman MAP[NBR. Y, NBR. X])) break; Arrive at the starting point (i.e. the position of the worker)


if (Block.isblank MAP[NBR. Y, NBR. X])///can go the road


{


Block.mark (ref MAP[NBR. Y, NBR. X], value); Mark, prevent the road from coming again


Q.enqueue (NBR); Join the queue, wait to continue looking for


}


}


if (Block.isman MAP[NBR. Y, NBR. X])) break; Reach the starting point


if (Q.count = = 0) return false; Unable to reach the starting point





to = Q.dequeue (); Out team, keep looking, this is breadth first search, because the front has been able to walk around all the way to join the queue.





}


return true; Find a route


}


}


}