Index: src/solver.d
==================================================================
--- src/solver.d
+++ src/solver.d
@@ -1,10 +1,19 @@
 //
 // http://en.wikipedia.org/wiki/F%C5%ABrinkazan
 //
 import util;
 import game;
+
+
+interface Solver
+{
+	// this(in Game g);
+	char single_step();
+	void force(char c);
+}
+
 
 bool is_spacy(char c)
 {
 	return c==' ' || c=='.' || c=='R' || c=='!' || c=='\\' || c=='O';
 }
@@ -97,15 +106,23 @@
 	}
 
 	return tuple(death, breath);
 }
 
-interface Solver
+class Queue(T)
 {
-	// this(in Game g);
-	char single_step();
-	void force(char c);
+	alias Tuple!(T,int) t;
+
+	t[] cur, next;
+
+	void push(T v, int p) { (cur.empty ? cur : next) ~= tuple(v,p); }
+	bool empty() { return cur.empty; }
+	t pop() {
+		t v = cur[0]; cur = cur[1..$];
+		if(cur.empty) { cur = next; next = null; }
+		return v;
+	}
 }
 
 ///
 /// Solver "Mountain":  be immovable like a mountain.
 ///
@@ -593,25 +610,10 @@
 		else if(s.g.dead) state = Tentative_Stuck;
 		return tuple(s, log, state);
 	}
 }
 
-class Queue(T)
-{
-	alias Tuple!(T,int) t;
-
-	t[] cur, next;
-
-	void push(T v, int p) { (cur.empty ? cur : next) ~= tuple(v,p); }
-	bool empty() { return cur.empty; }
-	t pop() {
-		t v = cur[0]; cur = cur[1..$];
-		if(cur.empty) { cur = next; next = null; }
-		return v;
-	}
-}
-
 ///
 /// Solver "Wind": let your rapidity be that of the wind.
 /// 
 class 疾如風 : Solver
 {
@@ -618,16 +620,25 @@
 	Game g;
 	this(in Game g)
 	{
 		this.g = g.clone();
 	}
+
+	string plan;
 
 	char single_step()
 	{
 		auto dm = death_move(g);
+		if( plan.empty || dm[0].count(plan[0]) ) {
+			plan = think(g, dm[0]);
+			if( plan.empty )
+				plan = "W";
+		}
 
-		char c = think(g, dm[0]);
+		char c = plan[0];
+		plan = plan[1..$];
+
 		if(c == 'W') {
 			wait_counter++;
 			if(dm[0].count(c) || wait_counter>=3) {
 				c = 'A';
 				foreach(char cc; "DLRU")
@@ -650,11 +661,11 @@
 			g.command(c);
 	}
 
 	int wait_counter = 0;
 
-	char think(in Game g, string death)
+	string think(in Game g, string death)
 	{
 		auto Q = new Queue!(Tuple!(Pos,Pos));
 		Q.push(tuple(g.map.robot.clone(), g.map.robot.clone()), 0);
 		Pos[][] V = new Pos[][](g.map.H+2, g.map.W+2);
 		while(!Q.empty) {
@@ -665,20 +676,19 @@
 			if(V[p.y][p.x])
 				continue;
 			V[p.y][p.x] = prev;
 			if(g.map[p]=='\\' || g.map[p]=='O')
 			{
-				Pos goback(Pos p) {
-					return V[p.y][p.x];
-				}
+				char[] trace;
 				for(;;) {
-					Pos q = goback(p);
-					if(q == g.map.robot)
-						if(q.y==p.y)
-							return q.x<p.x ? 'R' : 'L';
-						else
-							return q.y<p.y ? 'U' : 'D';
+					Pos q = V[p.y][p.x];
+					trace ~= (q.y==p.y ? (q.x<p.x ? 'R' : 'L') :
+					                     (q.y<p.y ? 'U' : 'D'));
+					if(q == g.map.robot) {
+						reverse(trace);
+						return trace.idup;
+					}
 					p=q;
 				}
 			}
 
 			int[4] dy=[-1,+1,0,0];
@@ -692,14 +702,14 @@
 					Q.push(tuple(new Pos(y,x),p), dist+1);
 				}
 			}
 		}
 
-		return 'W';
+		return "";
 	}
 }
 
 //alias 侵掠如火!(疾如風) MainSolver;
 //alias 侵掠如火!(徐如林) MainSolver;
 alias 疾如風 MainSolver;
 //alias 徐如林 MainSolver;
 //alias 不動如山 MainSolver;