Compilare: user.cpp: In function ‘void update_ldx()’: user.cpp:89:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < add[i].size(); ++ j) ^ user.cpp: In function ‘void sweep()’: user.cpp:100:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < add[i].size(); ++ j) ^ user.cpp:102:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < sub[i - dx + 1].size(); ++ j) ^ user.cpp: In function ‘void solve()’: user.cpp:114:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^ user.cpp: In function ‘void read()’: user.cpp:74:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.in", "r", stdin); ^ user.cpp:75:50: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &m, &n, &f, &dx, &dy); ^ user.cpp:79:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d", &px, &p.x, &py, &p.y, &p.cost); ^ user.cpp: In function ‘void write()’: user.cpp:120:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("demolish.out", "w", stdout); ^