View Compilation Error

0_0_6052049_21735.cpp: In function `int find(int)':
0_0_6052049_21735.cpp:8: error: `r' undeclared (first use this function)
0_0_6052049_21735.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6052049_21735.cpp: In function `void merge(int, int)':
0_0_6052049_21735.cpp:19: error: `r' undeclared (first use this function)
0_0_6052049_21735.cpp: In function `int main(int, char**)':
0_0_6052049_21735.cpp:30: error: `r' undeclared (first use this function)