train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:35:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < u.size(); i ++)
~~^~~~~~~~~~
train.cpp:38:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < a.size(); i ++)
~~^~~~~~~~~~
train.cpp:41:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < r.size(); i ++) {
~~^~~~~~~~~~
train.cpp:43:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int j = 0; j < r.size(); j ++)
~~^~~~~~~~~~
train.cpp:46:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int j = 0; j < r.size(); j ++)
~~^~~~~~~~~~
train.cpp:49:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int j = 0; j < r.size(); j ++) {
~~^~~~~~~~~~