diff --git a/solver_soft/Makefile b/solver_soft/Makefile
old mode 100755
new mode 100644
index 281361b44f4c2bd57a5d1964d3b4496c6a44f471..9a19afdb532f6f6762920af887d4467450bc72bc
--- a/solver_soft/Makefile
+++ b/solver_soft/Makefile
@@ -2,7 +2,7 @@ TARGET = sim
 OBJS = $(CPPS:.cpp=.o)
 CPPS = $(wildcard *.cpp)
 CXX = g++
-CXXFLAGS = -O3
+CXXFLAGS = -std=c++11 -O3
 
 all: $(TARGET)
 
diff --git a/solver_soft/solver.cpp b/solver_soft/solver.cpp
old mode 100755
new mode 100644
diff --git a/solver_soft/solver.hpp b/solver_soft/solver.hpp
old mode 100755
new mode 100644
diff --git a/solver_soft/tools.hpp b/solver_soft/tools.hpp
index 4ffdb2ab609296cc32eb892f2eef545ac9c64b4f..947061997e28d1c3e3b610713d593b37bf255ca9 100644
--- a/solver_soft/tools.hpp
+++ b/solver_soft/tools.hpp
@@ -13,4 +13,4 @@ void usage();
 void output_to_file(char *f_name, short int line_num, short int blocks, short int wi, short int hi, short int board[], pair<short int,short int> block_place[]);
 void show_result(short int line_num, short int blocks, short int wi, short int hi, short int board[], pair<short int,short int> block_place[]);
 
-#endif /* __TOOLS_HPP__ */
\ No newline at end of file
+#endif /* __TOOLS_HPP__ */