bash:/tmp$ g++ -Wall cpp.cpp 
cpp.cpp: In function ‘int main()’:
cpp.cpp:19:9: warning: unused variable ‘la’ [-Wunused-variable]
     int la=a.size();
         ^
cpp.cpp: In function ‘int mdr(int)’:
cpp.cpp:13:1: warning: control reaches end of non-void function [-Wreturn-type]
 }

No return in mdr function.

always use the following command for compiling: c++: g++ -O2 -static -Wl,--stack,268435456 -s -lm code.cpp c++11: g++ -std=c++0x -O2 -static -Wl,--stack,268435456 -s -lm -o code.cpp otherwise your code could have a different result from CF.