crocodile.cpp:10:1: error: 'set' does not name a type
set<pi>s;
^~~
crocodile.cpp: In function 'int travel_plan(int, int, int (*)[2], int*, int, int*)':
crocodile.cpp:20:9: error: 's' was not declared in this scope
s.insert( make_pair(0,P[i]) );
^
crocodile.cpp:23:13: error: 's' was not declared in this scope
while (!s.empty()) {
^
crocodile.cpp:33:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for (int i=0; i<graph[x.second].size(); i++) {
~^~~~~~~~~~~~~~~~~~~~~~~