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DijkstraAlgorithm.js
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73 lines (62 loc) · 1.85 KB
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const graphInfo = {
source: {A: 4, B: 1},
A: {C: 3, D: 5},
B: {A: 7, D: 2},
C: {D: 4, destination: 3},
D: {destination: 2},
destination: {}
};
// primary function
const dijkstra = (graph) => {
// shortest distance to each vertex
const distance = Object.assign(
{destination: Infinity}, graph.source);
// display path
const parentArray = {destination: null};
for (let child in graph.source) {
parentArray[child] = 'source';
}
// track vertexs that are marked
const marked = [];
let vertex = minimumDistancevertex(distance, marked);
while (vertex) {
let cost = distance[vertex];
let children = graph[vertex];
for (let n in children) {
let latestDistance = cost + children[n];
if (!distance[n]) {
distance[n] = latestDistance;
parentArray[n] = vertex;
}
if (distance[n] > latestDistance) {
distance[n] = latestDistance;
parentArray[n] = vertex;
}
}
marked.push(vertex);
vertex = minimumDistancevertex(distance, marked);
}
let shortestPath = ['destination'];
let parent = parentArray.destination;
while (parent) {
shortestPath.push(parent);
parent = parentArray[parent];
}
shortestPath.reverse();
const result = {
distance: distance.destination,
path: shortestPath
};
return result;
};
const minimumDistancevertex = (distance, marked) => {
return Object.keys(distance).reduce((lowest, vertex) => {
if (lowest === null || distance[vertex] < distance[lowest]) {
if (!marked.includes(vertex)) {
lowest = vertex;
}
}
return lowest;
}, null);
};
console.log(dijkstra(graphInfo));