Compilare: user.cpp: In function ‘void read()’: user.cpp:34:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<a.size(); i++) ^ user.cpp:38:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<a.size(); i++) ^ user.cpp:39:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<a[i].size(); j++) ^ user.cpp: In function ‘void vec(pt)’: user.cpp:64:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p.x!=s.size()-1 && s[p.x+1][p.y]!=INF2) ver(p.x+1,p.y,s[p.x][p.y]); ^ user.cpp:65:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (p.y!=s.size()-1 && s[p.x][p.y+1]!=INF2) ver(p.x,p.y+1,s[p.x][p.y]); ^ user.cpp: In function ‘void solve()’: user.cpp:70:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<x.size(); i++) ^ user.cpp: In function ‘void write()’: user.cpp:77:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<s.size(); i++,cout << '\n') ^ user.cpp:78:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<s[i].size(); j++) ^ user.cpp:76:9: warning: unused variable ‘c’ [-Wunused-variable] int c=0; ^ user.cpp: At global scope: user.cpp:84:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^