diff --git a/dynamic_programming/minimum_cost_path.py b/dynamic_programming/minimum_cost_path.py new file mode 100644 index 000000000..93d936656 --- /dev/null +++ b/dynamic_programming/minimum_cost_path.py @@ -0,0 +1,37 @@ +# Youtube Explaination: https://www.youtube.com/watch?v=lBRtnuxg-gU + +from typing import List + + +def minimum_cost_path(matrix: List[List[int]]) -> int: + ''' + Find the minimum cost traced by all possible paths from top left to bottom right in + a given matrix + + >>> minimum_cost_path([[2, 1], [3, 1], [4, 2]]) + 6 + + >>> minimum_cost_path([[2, 1, 4], [2, 1, 3], [3, 2, 1]]) + 7 + ''' + + # preprocessing the first row + for i in range(1, len(matrix[0])): + matrix[0][i] += matrix[0][i - 1] + + # preprocessing the first column + for i in range(1, len(matrix)): + matrix[i][0] += matrix[i - 1][0] + + # updating the path cost for current position + for i in range(1, len(matrix)): + for j in range(1, len(matrix[0])): + matrix[i][j] += min(matrix[i - 1][j], matrix[i][j - 1]) + + return matrix[-1][-1] + + +if __name__ == "__main__": + import doctest + + doctest.testmod()