Compilare: user.cpp: In function ‘long long int solveHist(int)’: user.cpp:24:81: warning: operation on ‘s’ may be undefined [-Wsequence-point] maxArea = MAX(maxArea, 1LL * hist[st[--s]] * (!s ? i : i - 1 - st[s - 1])); ^ user.cpp: In function ‘int main()’: user.cpp:36:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d%d", &n, &m); ^ user.cpp:39:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &mat[i][j]); ^