nicegift.cpp: In function 'int main()':
nicegift.cpp:36:29: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<std::vector<int> >::size_type {aka long unsigned int}' [-Wformat=]
printf("%d\n",ans.size());
~~~~~~~~~~^
nicegift.cpp:37:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i = 0;i<ans.size();i++){
~^~~~~~~~~~~
nicegift.cpp:39:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int j = 0;j<ans[i].size();j++){
~^~~~~~~~~~~~~~
nicegift.cpp:9:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d",&n,&k);
~~~~~^~~~~~~~~~~~~~
nicegift.cpp:12:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&a[i].first);
~~~~~^~~~~~~~~~~~~~~~~~