postmen.cpp: In function 'std::ostream& operator<<(std::ostream&, std::vector<int>&)':
postmen.cpp:77:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < x.size(); i++) {
~~^~~~~~~~~~
postmen.cpp:79:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (i != x.size() - 1) os << sp;
~~^~~~~~~~~~~~~~~
postmen.cpp: In function 'std::ostream& operator<<(std::ostream&, std::vector<std::pair<int, int> >&)':
postmen.cpp:88:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < x.size(); i++) os << x[i] << endl;
~~^~~~~~~~~~
postmen.cpp: In function 'int main()':
postmen.cpp:127:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i = 0; i < ans.size(); i++) {
~~^~~~~~~~~~~~
postmen.cpp:128:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int j = 0; j < ans[i].size(); j++) {
~~^~~~~~~~~~~~~~~
postmen.cpp:130:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (j != ans[i].size() - 1) printf(" ");
~~^~~~~~~~~~~~~~~~~~~~
postmen.cpp:120:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &n, &m);
~~~~~^~~~~~~~~~~~~~~~~
postmen.cpp:123:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &u, &v);
~~~~~^~~~~~~~~~~~~~~~~