@@ -5,31 +5,76 @@
 
 abstract class Output
 {
 	void command(char c);
+	void flush();
 }
 
 class NilOutput : Output
 {
 	override void command(char c) {}
+	override void flush() {}
 }
 
 class StdOutput : Output
 {
+	override void command(char c)
+	{
+		write(c);
+		stdout.flush();
+	}
+	override void flush() {}
+}
+
+// TODO: clean it up.
+__gshared Output g_output;
+
+class GuardedOutput : StdOutput
+{
 	// Handle SIGINT: force abort and exit.
 	static this()
 	{
 		signal(SIGINT, &sigint);
 	}
-	extern(C) static void sigint(int) {
-		write("A");
-		stdout.flush();
+
+	extern(C) static void sigint(int)
+	{
+		if(g_output !is null)
+			g_output.flush();
+		else {
+			write("A");
+			stdout.flush();
+		}
 		exit(0);
 	}
 
+	Game g;
+	this(Game ini) { this.g = ini.clone(); ideal_log ~= g.score_if_abort_now; g_output = this; }
+
+	string log;
+	long[] score_log;
+	long[] ideal_log;
+
 	override void command(char c)
 	{
-		// TODO: optimize redundancy.
-		write(c);
+		g.command(c);
+		log ~= c;
+		score_log ~= g.score;
+		ideal_log ~= g.score_if_abort_now;
+	}
+	override void flush()
+	{
+		Tuple!(long, int, int) cand;
+		cand[0] = long.min;
+		foreach(int i, long s; score_log)
+			if(cand[0] < s)	
+				cand = tuple(s,i,0);
+		foreach(int i, long s; ideal_log)
+			if(cand[0] < s)	
+				cand = tuple(s,i,1);
+		if(cand[2]==0)
+			writeln(log[0..cand[1]+1]);
+		else
+			writeln(log[0..cand[1]]~"A");
 		stdout.flush();
 	}
 }