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Refactor Floyd-Warshall tests.

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This commit is contained in:
Oleksii Trekhleb 2018-07-13 17:36:39 +03:00
parent 2874637d40
commit fafa52c26e
2 changed files with 29 additions and 27 deletions
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44
src/algorithms/graph/floyd-warshall/__test__/floydWarshall.test.js
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@ -55,7 +55,7 @@ describe('floydWarshall', () => {
.addEdge(edgeFG) .addEdge(edgeFG)
.addEdge(edgeEG); .addEdge(edgeEG);
const { distances, previousVertices } = floydWarshall(graph); const { distances, nextVertices } = floydWarshall(graph);
const vertices = graph.getAllVertices(); const vertices = graph.getAllVertices();
@ -77,13 +77,13 @@ describe('floydWarshall', () => {
expect(distances[vertexAIndex][vertexGIndex]).toBe(12); expect(distances[vertexAIndex][vertexGIndex]).toBe(12);
expect(distances[vertexAIndex][vertexFIndex]).toBe(11); expect(distances[vertexAIndex][vertexFIndex]).toBe(11);
expect(previousVertices[vertexAIndex][vertexFIndex]).toBe(vertexD); expect(nextVertices[vertexAIndex][vertexFIndex]).toBe(vertexD);
expect(previousVertices[vertexAIndex][vertexDIndex]).toBe(vertexB); expect(nextVertices[vertexAIndex][vertexDIndex]).toBe(vertexB);
expect(previousVertices[vertexAIndex][vertexBIndex]).toBe(vertexA); expect(nextVertices[vertexAIndex][vertexBIndex]).toBe(vertexA);
expect(previousVertices[vertexAIndex][vertexGIndex]).toBe(vertexE); expect(nextVertices[vertexAIndex][vertexGIndex]).toBe(vertexE);
expect(previousVertices[vertexAIndex][vertexCIndex]).toBe(vertexA); expect(nextVertices[vertexAIndex][vertexCIndex]).toBe(vertexA);
expect(previousVertices[vertexAIndex][vertexAIndex]).toBe(null); expect(nextVertices[vertexAIndex][vertexAIndex]).toBe(null);
expect(previousVertices[vertexAIndex][vertexHIndex]).toBe(null); expect(nextVertices[vertexAIndex][vertexHIndex]).toBe(null);
}); });
it('should find minimum paths to all vertices for directed graph', () => { it('should find minimum paths to all vertices for directed graph', () => {
@ -119,7 +119,7 @@ describe('floydWarshall', () => {
.addEdge(edgeCA) .addEdge(edgeCA)
.addEdge(edgeCD); .addEdge(edgeCD);
const { distances, previousVertices } = floydWarshall(graph); const { distances, nextVertices } = floydWarshall(graph);
const vertices = graph.getAllVertices(); const vertices = graph.getAllVertices();
@ -140,11 +140,11 @@ describe('floydWarshall', () => {
[2, 5, 7, 0], [2, 5, 7, 0],
]); ]);
expect(previousVertices[vertexAIndex][vertexDIndex]).toBe(vertexC); expect(nextVertices[vertexAIndex][vertexDIndex]).toBe(vertexC);
expect(previousVertices[vertexAIndex][vertexCIndex]).toBe(vertexB); expect(nextVertices[vertexAIndex][vertexCIndex]).toBe(vertexB);
expect(previousVertices[vertexBIndex][vertexDIndex]).toBe(vertexC); expect(nextVertices[vertexBIndex][vertexDIndex]).toBe(vertexC);
expect(previousVertices[vertexAIndex][vertexAIndex]).toBe(null); expect(nextVertices[vertexAIndex][vertexAIndex]).toBe(null);
expect(previousVertices[vertexAIndex][vertexBIndex]).toBe(vertexA); expect(nextVertices[vertexAIndex][vertexBIndex]).toBe(vertexA);
}); });
it('should find minimum paths to all vertices for directed graph with negative edge weights', () => { it('should find minimum paths to all vertices for directed graph with negative edge weights', () => {
@ -188,7 +188,7 @@ describe('floydWarshall', () => {
.addEdge(edgeCB) .addEdge(edgeCB)
.addEdge(edgeBA); .addEdge(edgeBA);
const { distances, previousVertices } = floydWarshall(graph); const { distances, nextVertices } = floydWarshall(graph);
const vertices = graph.getAllVertices(); const vertices = graph.getAllVertices();
@ -208,11 +208,13 @@ describe('floydWarshall', () => {
expect(distances[vertexFIndex][vertexDIndex]).toBe(9); expect(distances[vertexFIndex][vertexDIndex]).toBe(9);
expect(distances[vertexFIndex][vertexEIndex]).toBe(8); expect(distances[vertexFIndex][vertexEIndex]).toBe(8);
expect(previousVertices[vertexFIndex][vertexGIndex]).toBe(null); expect(nextVertices[vertexFIndex][vertexGIndex]).toBe(null);
expect(previousVertices[vertexFIndex][vertexFIndex]).toBe(null); expect(nextVertices[vertexFIndex][vertexFIndex]).toBe(null);
// expect(previousVertices[vertexFIndex][vertexBIndex]).toBe(vertexC); expect(nextVertices[vertexAIndex][vertexBIndex]).toBe(vertexC);
// expect(previousVertices[vertexFIndex][vertexCIndex].getKey()).toBe(vertexA.getKey()); expect(nextVertices[vertexAIndex][vertexCIndex]).toBe(vertexA);
// expect(previousVertices[vertexFIndex][vertexAIndex]).toBe(vertexD); expect(nextVertices[vertexFIndex][vertexBIndex]).toBe(vertexE);
// expect(previousVertices[vertexFIndex][vertexDIndex]).toBe(vertexE); expect(nextVertices[vertexEIndex][vertexBIndex]).toBe(vertexD);
expect(nextVertices[vertexDIndex][vertexBIndex]).toBe(vertexC);
expect(nextVertices[vertexCIndex][vertexBIndex]).toBe(vertexC);
}); });
}); });

12
src/algorithms/graph/floyd-warshall/floydWarshall.js
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@ -1,6 +1,6 @@
/** /**
* @param {Graph} graph * @param {Graph} graph
* @return {{distances: number[][], previousVertices: GraphVertex[][]}} * @return {{distances: number[][], nextVertices: GraphVertex[][]}}
*/ */
export default function floydWarshall(graph) { export default function floydWarshall(graph) {
// Get all graph vertices. // Get all graph vertices.
@ -8,7 +8,7 @@ export default function floydWarshall(graph) {
// Init previous vertices matrix with nulls meaning that there are no // Init previous vertices matrix with nulls meaning that there are no
// previous vertices exist that will give us shortest path. // previous vertices exist that will give us shortest path.
const previousVertices = Array(vertices.length).fill(null).map(() => { const nextVertices = Array(vertices.length).fill(null).map(() => {
return Array(vertices.length).fill(null); return Array(vertices.length).fill(null);
}); });
@ -33,7 +33,7 @@ export default function floydWarshall(graph) {
// There is an edge from vertex with startIndex to vertex with endIndex. // There is an edge from vertex with startIndex to vertex with endIndex.
// Save distance and previous vertex. // Save distance and previous vertex.
distances[startIndex][endIndex] = edge.weight; distances[startIndex][endIndex] = edge.weight;
previousVertices[startIndex][endIndex] = startVertex; nextVertices[startIndex][endIndex] = startVertex;
} else { } else {
distances[startIndex][endIndex] = Infinity; distances[startIndex][endIndex] = Infinity;
} }
@ -60,13 +60,13 @@ export default function floydWarshall(graph) {
if (distances[startIndex][endIndex] > distViaMiddle) { if (distances[startIndex][endIndex] > distViaMiddle) {
// We've found a shortest pass via middle vertex. // We've found a shortest pass via middle vertex.
distances[startIndex][endIndex] = distViaMiddle; distances[startIndex][endIndex] = distViaMiddle;
previousVertices[startIndex][endIndex] = middleVertex; nextVertices[startIndex][endIndex] = middleVertex;
} }
}); });
}); });
}); });
// Shortest distance from x to y: distance[x][y]. // Shortest distance from x to y: distance[x][y].
// Previous vertex of shortest path from x to y: previousVertices[x][y]. // Next vertex after x one in path from x to y: nextVertices[x][y].
return { distances, previousVertices }; return { distances, nextVertices };
} }