src.cpp:1:8: error: 'horizontal_fold_sums' does not name a type
horizontal_fold_sums[i - 1] = row_counts[0] + row_counts[i];
^
src.cpp:2:9: error: 'vertical_fold_sums' does not name a type
vertical_fold_sums[i - 1] = col_counts[0] + col_counts[i];
^
src.cpp:3:5: error: expected declaration before '}' token
}
^