Flood Fill Four-Way Algorithm Complexity

Question

I\'ve searched but I can\'t seem to find the complexity of the Flood Fill Algorithm (Four-way ver.). What exactly is the complexity in big O notation?

Answer 1

The time complexity of the Flood Fill algorithm should be O(m×n) , where m= no. of rows and n=no. of columns in the given matrix. Note that every element of matrix is processed at most three times. So, it boils down to O(3×mn), which eventually is same as O(mn).