Compilare: user.cpp: In function ‘void bfs()’: user.cpp:48:62: warning: statement has no effect [-Wunused-value] if (j - 1 >= 1 && !V[i][j - 1] && G[i][j] != 1){ V[i][j - 1]; q.push(make_pair(i, j - 1)); dist[i][j - 1] = dist[i][j] + 1; } ^ user.cpp: In function ‘int main()’: user.cpp:58:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j!=s.size()){ ^ user.cpp:72:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j!=s.size()){ ^ user.cpp:87:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j!=s.size()){ ^ user.cpp:95:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j!=s.size()){ ^ user.cpp:117:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j < s.size()){ ^ user.cpp:148:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j != s.size()){ ^ user.cpp:177:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (j != s.size()){ ^