/tmp/cceE6zZ1.o: In function `main':
driver.cpp:(.text.startup+0x8e): undefined reference to `size(opaque_list*)'
driver.cpp:(.text.startup+0xe0): undefined reference to `unique(opaque_list*)'
driver.cpp:(.text.startup+0x128): undefined reference to `isIncreasing(opaque_list*)'
driver.cpp:(.text.startup+0x17b): undefined reference to `memberOf(opaque_list*, int)'
driver.cpp:(.text.startup+0x1b0): undefined reference to `isArithmeticSequence(opaque_list*)'
driver.cpp:(.text.startup+0x1e8): undefined reference to `reverse(opaque_list*)'
driver.cpp:(.text.startup+0x234): undefined reference to `append(opaque_list*, opaque_list*)'
driver.cpp:(.text.startup+0x279): undefined reference to `dot(opaque_list*, opaque_list*)'
driver.cpp:(.text.startup+0x2aa): undefined reference to `filter_odd(opaque_list*)'
driver.cpp:(.text.startup+0x2f3): undefined reference to `filter(opaque_list*, bool (*)(int))'
driver.cpp:(.text.startup+0x34d): undefined reference to `insert_list(opaque_list*, opaque_list*, unsigned int)'
driver.cpp:(.text.startup+0x391): undefined reference to `chop(opaque_list*, unsigned int)'
driver.cpp:(.text.startup+0x3c2): undefined reference to `tree_sum(opaque_tree*)'
driver.cpp:(.text.startup+0x406): undefined reference to `tree_search(opaque_tree*, int)'
driver.cpp:(.text.startup+0x437): undefined reference to `depth(opaque_tree*)'
driver.cpp:(.text.startup+0x486): undefined reference to `tree_max(opaque_tree*)'
driver.cpp:(.text.startup+0x4b7): undefined reference to `traversal(opaque_tree*)'
driver.cpp:(.text.startup+0x4fc): undefined reference to `covered_by(opaque_tree*, opaque_tree*)'
driver.cpp:(.text.startup+0x541): undefined reference to `contained_by(opaque_tree*, opaque_tree*)'
driver.cpp:(.text.startup+0x585): undefined reference to `insert_tree(int, opaque_tree*)'
driver.cpp:(.text.startup+0x5ca): undefined reference to `tree_hasMonotonicPath(opaque_tree*)'
driver.cpp:(.text.startup+0x60e): undefined reference to `tree_allPathSumGreater(opaque_tree*, int)'
collect2: error: ld returned 1 exit status