message: Update unique-paths-iii.cpp
diff: @@ -57,6 +57,7 @@ private:
  0 <= c && c < grid[0].size() &&
  grid[r][c] % 2 == 0 &&
  todo & index(grid, r, c)) {
  +
  result += dp(grid, make_pair(r, c), dst,
  todo ^ index(grid, r, c), lookup);
  }
  