diff -r 9be6981ea598 NQueens/Makefile
--- a/NQueens/Makefile	Thu Jul 04 02:05:53 2013 +0900
+++ b/NQueens/Makefile	Fri Mar 07 23:11:16 2014 +0900
@@ -1,7 +1,6 @@
 
 CXX = g++
 CPPFLAGS = -Wall -O2 -g
-LDFLAGS = -lpthread
 RM = rm -f
 
 TARGETS = nqueens
diff -r 9be6981ea598 NQueens/nqueens.cpp
--- a/NQueens/nqueens.cpp	Thu Jul 04 02:05:53 2013 +0900
+++ b/NQueens/nqueens.cpp	Fri Mar 07 23:11:16 2014 +0900
@@ -4,7 +4,8 @@
 #include <cstring>
 
 #include "solver.h"
-#include "thread.h"
+#include <stdexcept>
+using namespace std;
 #include "timenow.h"
 
 #if defined(_WIN32)
@@ -18,46 +19,32 @@
 int safe_main(int argc, char *argv[])
 {
 	int n;
-	int parallel;
 	long answer;
 	int center, x, row, left, right;
 	long long start, elapse;
 	Solver **solvers;
-	Thread **solver_threads;
 	Solver *solver_remain;
-	Thread *solver_remain_thread;
 
 	if (argc < 2) {
-		cout << "usage: \n"
-		    << "NQueens queens(1 ... 30) parallel(true or false)"
-		    << endl;
-		return -1;
+		cout << "n" << endl;
+		cin >> n;
 	}
 
+else{
 	//get the arguments
 	n = strtol(argv[1], NULL, 0);
 	if (n < 0 || 30 < n) {
 		n = 0;
 	}
+}
 	cout << "queens  : " << n << endl;
 
-	parallel = false;
-	if (argc >= 3) {
-		if (strcasecmp(argv[2], "true") == 0) {
-			parallel = 1;
-		} else {
-			parallel = 0;
-		}
-	}
-	cout << "parallel: " << parallel << endl;
-
 	//start
 	start = TimeNow::microtime();
 
 	//solve
 	center = n >> 1;
 	solvers = new Solver *[center];
-	solver_threads = new Thread *[center];
 
 	answer = 0;
 	for (x = 0; x < center; x++) {
@@ -67,16 +54,10 @@
 		right = row >> 1;
 
 		solvers[x] = new Solver(row, left, right, n, 1, 0);
-		solver_threads[x] = new Thread(solvers[x]);
-		if (parallel) {
-			solver_threads[x]->start();
-		} else {
-			solver_threads[x]->run();
-		}
+			solvers[x]->run();
 	}
 
 	solver_remain = NULL;
-	solver_remain_thread = NULL;
 	if (n % 2 == 1) {
 		//center(if N is odd)
 		row = 1 << center;
@@ -84,39 +65,25 @@
 		right = row >> 1;
 
 		solver_remain = new Solver(row, left, right, n, 1, 0);
-		solver_remain_thread = new Thread(solver_remain);
-		if (parallel) {
-			solver_remain_thread->start();
-		} else {
-			solver_remain_thread->run();
-		}
+			solver_remain->run();
 	}
 
 	//join
 	for (x = 0; x < center; x++) {
-		if (parallel) {
-			solver_threads[x]->join();
-		}
 		answer += solvers[x]->get_new_answer();
 	}
 	answer *= 2;
 
 	if (solver_remain) {
-		if (parallel) {
-			solver_remain_thread->join();
-		}
 		answer += solver_remain->get_new_answer();
 	}
 
 	//delete
 	for (x = 0; x < center; x++) {
 		delete solvers[x];
-		delete solver_threads[x];
 	}
 	delete[] solvers;
-	delete[] solver_threads;
 	delete solver_remain;
-	delete solver_remain_thread;
 
 	//finished
 	elapse = TimeNow::microtime() - start;