Kursinhalt
Dynamic Programming
Dynamic Programming
Problem B. Minimum path
Let's traverse mat and update values in it: now mat[i][j] contains the path cost to cell [i, j]. How to reach that? You can get to the mat[i][j] from either mat[i-1][j] or mat[i][j-1] cell, that also contain the path cost to themselves. Thus, mat[i][j] can be updated as:
mat[i][j] += min(mat[i-1][j], mat[i][j-1]),
since you choose the minumum cost path between these two.
Note that some cells can be reached only from left or right, for example, mat[0][j] (only from mat[0][j-1]).
So, the goal is to traverse mat and update its values; after that, return path cost at mat[-1][-1].
def minPath(mat): m, n = len(mat), len(mat[0]) for i in range(1, m): mat[i][0] += mat[i-1][0] for j in range(1, n): mat[0][j] += mat[0][j-1] for i in range(1, m): for j in range(1, n): mat[i][j] += min(mat[i-1][j], mat[i][j-1]) return mat[-1][-1] mat = [[10,1,23,4,5,1], [2,13,20,9,1,5], [14,3,3,6,12,7]] print(minPath(mat))
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Problem B. Minimum path
Let's traverse mat and update values in it: now mat[i][j] contains the path cost to cell [i, j]. How to reach that? You can get to the mat[i][j] from either mat[i-1][j] or mat[i][j-1] cell, that also contain the path cost to themselves. Thus, mat[i][j] can be updated as:
mat[i][j] += min(mat[i-1][j], mat[i][j-1]),
since you choose the minumum cost path between these two.
Note that some cells can be reached only from left or right, for example, mat[0][j] (only from mat[0][j-1]).
So, the goal is to traverse mat and update its values; after that, return path cost at mat[-1][-1].
def minPath(mat): m, n = len(mat), len(mat[0]) for i in range(1, m): mat[i][0] += mat[i-1][0] for j in range(1, n): mat[0][j] += mat[0][j-1] for i in range(1, m): for j in range(1, n): mat[i][j] += min(mat[i-1][j], mat[i][j-1]) return mat[-1][-1] mat = [[10,1,23,4,5,1], [2,13,20,9,1,5], [14,3,3,6,12,7]] print(minPath(mat))
Wechseln Sie zum Desktop, um in der realen Welt zu übenFahren Sie dort fort, wo Sie sind, indem Sie eine der folgenden Optionen verwendenDanke für Ihr Feedback!
Wechseln Sie zum Desktop, um in der realen Welt zu übenFahren Sie dort fort, wo Sie sind, indem Sie eine der folgenden Optionen verwenden