Compilare: main.cpp: In function 'void buildLevel(int)': main.cpp:22:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < cells[lvl].size(); i++){ ~~^~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:67:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ main.cpp:70:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^