View Compilation Error

0_0_11158904_32736.cpp:4: error: `usingnamespace' does not name a type
0_0_11158904_32736.cpp: In function `bool dfs(int)':
0_0_11158904_32736.cpp:21: error: `returntrue' undeclared (first use this function)
0_0_11158904_32736.cpp:21: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_11158904_32736.cpp:22: error: `returnfalse' undeclared (first use this function)