message: Update minimum-number-of-days-to-disconnect-island.cpp
diff: @@ -46,9 +46,8 @@ private:
  (*lookup)[i][j] = 1;
  while (!stk.empty()) {
  auto [i, j] = stk.back(); stk.pop_back();
  - for (const auto [di, dj] : directions) {
  - const auto [ni, nj] = pair(i + di, j + dj);
  -
  + for (const auto& [di, dj] : directions) {
  + const auto& [ni, nj] = pair(i + di, j + dj);
  if (!(0 <= ni && ni < grid.size() &&
  0 <= nj && nj < grid[0].size() &&
  grid[ni][nj] &&
  