View Compilation Error

0_0_2957248_24237.cpp:5: error: `maxn' was not declared in this scope
0_0_2957248_24237.cpp: In function `void build(int, int, int)':
0_0_2957248_24237.cpp:9: error: `tree' undeclared (first use this function)
0_0_2957248_24237.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2957248_24237.cpp: In function `void update(int, int, int, int)':
0_0_2957248_24237.cpp:22: error: `tree' undeclared (first use this function)
0_0_2957248_24237.cpp: In function `int Que(int, int, int)':
0_0_2957248_24237.cpp:53: error: `tree' undeclared (first use this function)
0_0_2957248_24237.cpp: In function `int main()':
0_0_2957248_24237.cpp:76: error: `scanf' undeclared (first use this function)
0_0_2957248_24237.cpp:85: error: `tree' undeclared (first use this function)
0_0_2957248_24237.cpp:95: error: `printf' undeclared (first use this function)