junlindu / bear-map Goto Github PK

https://github.com/JunlinDu/bear-map-project/blob/45bc72643116e303de00cf04ef219725a69e036c/src/main/java/Rasterer.java#L58-L78

Corner cases such as users explore areas completely outside of the map have not been handled when constructing the result. Require fix after major features are implemented.

The Retrieval tree can be optimized by:

1. Having each node storing a value and the best value of its substring, so that the tree will not have to loop through all of its children, but instead look for children in the order of "best".
2. using a priority queue to implement the feature.

Null Pointer Exception is thrown when provided string has no match in the tree

https://github.com/JunlinDu/bear-map-project/blob/826619dccb74f9c33048d695e45ec96c58759562/src/main/java/Router/ArrayHeapMinPQ.java#L146-L156

RemoveSmallest() returns null when removing an item from the heap of lowest priority value where the item to be removed is the only item left in the heap, which will in turn causes the implementation of Dijkstra's algorithm to throw a null pointer exception.

https://github.com/JunlinDu/bear-map-project/blob/ecd77f35b5acb998c2cb602e971a1aa70972bef3/src/main/java/Router/ArrayHeapMinPQ.java#L167-L177
changePriority is not working properly as the call to test41to46() and test66to55() in TestRouterTiny will throw following exceptions:

java.util.NoSuchElementException
at Router.ArrayHeapMinPQ.changePriority(ArrayHeapMinPQ.java:169)
at Router.Router.relaxEdgeFrom(Router.java:76)
at Router.Router.shortestPath(Router.java:59)
at TestRouterTiny.test41to46(TestRouterTiny.java:50)

java.util.NoSuchElementException
at Router.ArrayHeapMinPQ.changePriority(ArrayHeapMinPQ.java:169)
at Router.Router.relaxEdgeFrom(Router.java:76)
at Router.Router.shortestPath(Router.java:59)
at TestRouterTiny.test66to55(TestRouterTiny.java:61)

Update The issue is believed to be linked with sink() in ArrayMinPQ().
Note sink() has never been tested before

https://github.com/JunlinDu/bear-map-project/blob/ecd77f35b5acb998c2cb602e971a1aa70972bef3/src/main/java/Router/ArrayHeapMinPQ.java#L104-L115

https://github.com/JunlinDu/bear-map-project/blob/5af3c84270e324ea93b8ba696889ac2a6b489612/src/main/java/Router/Router.java#L209-L251

Bearing function will return incorrect direction when turning sharp left.

https://github.com/JunlinDu/bear-map-project/blob/45bc72643116e303de00cf04ef219725a69e036c/src/main/java/GraphBuilder/GraphDB.java#L55-L74

Inner-class Edge might not be required, since distance() calculates the distance between two nodes. However, the removal of the Edge class might require refactoring in GraphBuildingHandler and GraphDB.
The justification for keeping this class might be an improvement in performance in runtime, which also requires refactoring of GraphDB class.
This is to be determined after path searching implementation is done.

https://github.com/JunlinDu/bear-map-project/blob/2d3eb6892cd245d5363fa53f3b3b4fa73ec5c39a/src/main/java/GraphBuilder/GraphDB.java#L40

A node can exist in multiple ways. The current implementation will cause navigation errors.