lite-pathfindings/dist/algorithms/Floyd-Warshall.js

Simple, intuitive and lightweight pathfinding algorithms

"use strict";

module.exports = {
  init: function init(dist) {
    var v = dist.length;
    var next = initNext(dist);

    for (var k = 0; k < v; k++) {
      for (var i = 0; i < v; i++) {
        for (var j = 0; j < v; j++) {
          if (dist[i][j] > dist[i][k] + dist[k][j]) {
            dist[i][j] = dist[i][k] + dist[k][j];
            next[i][j] = next[i][k];
          }
        }
      }
    }return next;
  },
  getPath: function getPath(next, u, v) {
    if (next[u][v] == undefined) return [];

    var path = [u];

    while (u != v) {
      u = next[u][v];
      path.push(u);
    }

    return path;
  },
  getWeight: function getWeight(matrix, vertex1, vertex2) {
    return matrix[vertex1][vertex2];
  },
  containNegativeCycle: function containNegativeCycle(matrix) {
    var length = matrix.length;
    for (var i = 0; i < length; i++) {
      for (var j = 0; j < length; j++) {
        if (matrix[i][j] < 0) return true;
      }
    }
    return false;
  }
};

var initNext = function initNext(dist) {
  var v = dist.length;
  var next = new Array(v);

  for (var i = 0; i < v; i++) {
    next[i] = new Array(v);

    for (var j = 0; j < v; j++) {
      if (isFinite(dist[i][j]) && dist[i][j] != 0) next[i][j] = j;
    }
  }

  return next;
};