85 lines
2.5 KiB
JavaScript
85 lines
2.5 KiB
JavaScript
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(function (exports) {
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'use strict';
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var floydWarshall = (function () {
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/**
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* Matrix used for the algorithm.
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*/
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var dist;
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/**
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* Initialize the distance matrix.
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*
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* @private
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* @param {Array} graph Distance matrix of the array.
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* @return {Array} Distance matrix used for the algorithm.
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*/
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function init(graph) {
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var dist = [];
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var size = graph.length;
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for (var i = 0; i < size; i += 1) {
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dist[i] = [];
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for (var j = 0; j < size; j += 1) {
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if (i === j) {
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dist[i][j] = 0;
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} else if (!isFinite(graph[i][j])) {
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dist[i][j] = Infinity;
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} else {
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dist[i][j] = graph[i][j];
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}
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}
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}
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return dist;
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}
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/**
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* Floyd-Warshall algorithm. Finds the shortest path between
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* each two vertices.<br><br>
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* Complexity: O(|V|^3) where V is the number of vertices.
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*
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* @public
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* @module graphs/shortest-path/floyd-warshall
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* @param {Array} graph A distance matrix of the graph.
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* @return {Array} Array which contains the shortest
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* distance between each two vertices.
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*
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* @example
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* var floydWarshall =
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* require('path-to-algorithms/src/graphs/shortest-path/floyd-warshall').floydWarshall;
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* var distMatrix =
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* [[Infinity, 7, 9, Infinity, Infinity, 16],
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* [7, Infinity, 10, 15, Infinity, Infinity],
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* [9, 10, Infinity, 11, Infinity, 2],
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* [Infinity, 15, 11, Infinity, 6, Infinity],
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* [Infinity, Infinity, Infinity, 6, Infinity, 9],
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* [16, Infinity, 2, Infinity, 9, Infinity]];
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*
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* // [ [ 0, 7, 9, 20, 20, 11 ],
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* // [ 7, 0, 10, 15, 21, 12 ],
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* // [ 9, 10, 0, 11, 11, 2 ],
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* // [ 20, 15, 11, 0, 6, 13 ],
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* // [ 20, 21, 11, 6, 0, 9 ],
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* // [ 11, 12, 2, 13, 9, 0 ] ]
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* var shortestDists = floydWarshall(distMatrix);
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*/
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return function (graph) {
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dist = init(graph);
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var size = graph.length;
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for (var k = 0; k < size; k += 1) {
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for (var i = 0; i < size; i += 1) {
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for (var j = 0; j < size; j += 1) {
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if (dist[i][j] > dist[i][k] + dist[k][j]) {
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dist[i][j] = dist[i][k] + dist[k][j];
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}
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}
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}
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}
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return dist;
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};
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}());
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exports.floydWarshall = floydWarshall;
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})(typeof window === 'undefined' ? module.exports : window);
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