gondola.cpp: In function 'int valid(int, int*)':
gondola.cpp:17:7: error: 'all' was not declared in this scope
sort(all(b));
^~~
gondola.cpp:17:7: note: suggested alternative: 'll'
sort(all(b));
^~~
ll
gondola.cpp:18:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i =1;i<b.size();i++)if(b[i]==b[i-1]) return 0;
~^~~~~~~~~
gondola.cpp:23:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(++i; i < v.size(); i++) {
~~^~~~~~~~~~