[BUG] deleteVertex deletes all of it's neighbors from the inEdge Map, even when that neighbor still has Vertex's outgoing to it

[jasonmacdonald]

Describe the bug Mostly what the title says.

Here is a simple reproduction

const graph = new DirectedGraph();
graph.addVertex('A');
graph.addVertex('B');
graph.addVertex('C');

graph.addEdge('B', 'A');
graph.addEdge('C', 'A');

// 'Incoming to A should contain ['B','C']
console.log(graph.incomingEdgesOf('A').map((e) => e.src)); //  ['B','C']

// Now delete B, which has no direct link to C, only that C -> A.
graph.deleteVertex('B');

// Now if we do the same call to incoming edges for A we should get only ['C']
console.log(
    graph.incomingEdgesOf('A').map((e) => e.src), // []
);

// but it only shows an empty array, since we deleted all of `A's edges, not just the one to `B`.

// If we check C, it correctly shows A as an outgoing edge, 
// even though A no longer has any knowledge of C linking to it.
console.log(graph.outgoingEdgesOf('C').map((e) => e.dest));

Unless I'm fundamentally misunderstanding how this should work, deleting B should not wipe out all incoming edges to A, only the edges pointing at B.

I tracked the issue here https://github.com/zrwusa/data-structure-typed/blob/main/src/data-structures/graph/directed-graph.ts#L264, which I believe should be deleting an edge inside A's set of edges, not all of A's edges.

[jasonmacdonald]

Changing that line from this._inEdgeMap.delete(neighbor); to this.deleteEdgeSrcToDest(vertex, neighbor); appears to fix the issue.