books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:32:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0; i <= cycles.size(); ++i) {
~~^~~~~~~~~~~~~~~~
books.cpp:33:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
ans = min(ans, (i != cycles.size() ? -cycles[i].first : 0) * 2 + cur);
~~^~~~~~~~~~~~~~~~
books.cpp:34:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
ans = min(ans, (i != cycles.size() ? -cycles[i].first : 0) + cur * 2);
~~^~~~~~~~~~~~~~~~
books.cpp:35:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(i != cycles.size()) cur = max(cur, cycles[i].second);
~~^~~~~~~~~~~~~~~~