improve floyd

64json · 64json · commit 5b3cfc8b881b · 2016-06-04T01:15:58.000+09:00
diff --git a/algorithm/graph_search/floyd_warshall/shortest_paths/code.js b/algorithm/graph_search/floyd_warshall/shortest_paths/code.js
@@ -1,33 +1,40 @@
 function FloydWarshall() {
-    // Finds the shortest path between all nodes
-    var S = new Array(G.length);
-    for (var i = 0; i < G.length; i++) S[i] = new Array(G.length)
+  // Finds the shortest path between all nodes
+  var S = new Array(G.length);
+  for (var i = 0; i < G.length; i++) S[i] = new Array(G.length)
+  for (i = 0; i < G.length; i++) {
+    for (var j = 0; j < G.length; j++) {
+      // Distance to self is always 0
+      if (i == j) S[i][i] = 0;
+      // Distance between connected nodes is their weight
+      else if (G[i][j] > 0) {
+        S[i][j] = G[i][j];
+      }// Else we don't know the distance and we set it to infinity
+      else S[i][j] = MAX_VALUE;
+    }
+  }
+  // If there is a shorter path using k, use it instead
+  for (var k = 0; k < G.length; k++) {
     for (i = 0; i < G.length; i++) {
-        tracer._visit(i)._wait();
-        for (var j = 0; j < G.length; j++) {
-            // Distance to self is always 0
-            if (i == j) S[i][i] = 0;
-            // Distance between connected nodes is their weight
-            else if (G[i][j] > 0) {
-                S[i][j] = G[i][j];
-                tracer._visit(j, i, S[i][j])._wait();
-                tracer._leave(j, i, S[i][j])._wait();
-            }// Else we don't know the distance and we set it to infinity
-            else S[i][j] = MAX_VALUE;
+      if (k == i) continue;
+      tracer._visit(k, i)._wait();
+      for (j = 0; j < G.length; j++) {
+        if (i == j || j == k) continue;
+        tracer._visit(j, k)._wait();
+        if (S[i][j] > S[i][k] + S[k][j]) {
+          tracer._visit(j, i, S[i][j])._wait();
+          S[i][j] = S[i][k] + S[k][j];
+          tracer._leave(j, i, S[i][j]);
         }
-        tracer._leave(i)._wait();
+        tracer._leave(j, k);
+      }
+      tracer._leave(k, i)._wait();
     }
-    // If there is a shorter path using k, use it instead
-    for (var k = 0; k < G.length; k++)
-        for (i = 0; i < G.length; i++)
-            for (j = 0; j < G.length; j++)
-                if (S[i][j] > S[i][k] + S[k][j])
-                    S[i][j] = S[i][k] + S[k][j];
-    for (i = 0; i < G.length; i++)
-        for (j = 0; j < G.length; j++)
-            if (S[i][j] == MAX_VALUE) logger._print('there is no path from ' + i + ' to ' + j);
-            else logger._print('the shortest path from ' + i +
-                ' to ' + j + ' is ' + S[i][j]);
+  }
+  for (i = 0; i < G.length; i++)
+    for (j = 0; j < G.length; j++)
+      if (S[i][j] == MAX_VALUE) logger._print('there is no path from ' + i + ' to ' + j);
+      else logger._print('the shortest path from ' + i + ' to ' + j + ' is ' + S[i][j]);
 }
 var MAX_VALUE = Infinity;
 logger._print('finding the shortest paths from and to all nodes');
diff --git a/algorithm/graph_search/floyd_warshall/shortest_paths/data.js b/algorithm/graph_search/floyd_warshall/shortest_paths/data.js
@@ -1,12 +1,5 @@
 var tracer = new WeightedDirectedGraphTracer();
 var logger = new LogTracer();
 tracer.attach(logger);
-/*var G = [ // G[i][j] indicates the weight of the path from the i-th node to the j-th node
- [0, 3, 0, 1, 0],
- [5, 0, 1, 2, 4],
- [1, 0, 0, 2, 0],
- [0, 2, 0, 0, 1],
- [0, 1, 3, 0, 0]
- ];*/
-var G = WeightedDirectedGraph.random(10, .4, 1, 9);
+var G = WeightedDirectedGraph.random(5, 1, 1, 9);
 tracer._setData(G);
