railroad.cpp: In function 'void dfs(int)':
railroad.cpp:15:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < g[v].size(); i++){
~~^~~~~~~~~~~~~
railroad.cpp: In function 'long long int plan_roller_coaster(std::vector<int>, std::vector<int>)':
railroad.cpp:28:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < s.size(); i++){
~~^~~~~~~~~~
railroad.cpp:34:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < s.size(); i++){
~~^~~~~~~~~~
railroad.cpp:42:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < zhat.size(); i++){
~~^~~~~~~~~~~~~
railroad.cpp:51:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < zhat.size(); i++)
~~^~~~~~~~~~~~~