[Leetcode] (python): 064-minimum Path Sum

Source of the topic:

https://leetcode.com/problems/minimum-path-sum/

Test Instructions Analysis:

Given a nonnegative matrix of MXN, find a way to make all the numbers from (0,0) to (m-1,n-1) pass and the smallest (similar to the last two questions, only downward and upward).

Topic Ideas:

Similar to the previous question, use a two-dimensional matrix a[i][j] to represent the smallest and from (0,0) to (I,J). Then a[i][j] = min (a[i-1][j],a[i][j-1]) + nums[i][j]. So this is also a dynamic programming problem, just need to put a's entire table out on it. The complexity of Time is O (MXN).

Code (Python):

　　

1 classsolution (object):2     defminpathsum (Self, grid):3         """4 : Type Grid:list[list[int]]5 : Rtype:int6         """7M,n =len (GRID), Len (grid[0])8ans = [[0 forIinchRange (n)] forJinchrange (m)]9Ans[0][0] =Grid[0][0]Ten          forIinchRange (m): One              forJinchrange (n): A                 ifI!=0 andj = =0: -ANS[I][J] = Ans[i-1][j] +Grid[i][j] -                 elifi = = 0 andJ! =0: theANS[I][J] = ans[i][j-1] +Grid[i][j] -                 elifI! = 0 andJ! =0: -Ans[i][j] = min (ans[i-1][j],ans[i][j-1]) +Grid[i][j] -         returnANS[M-1][N-1]

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Reprint Please specify source: http://www.cnblogs.com/chruny/p/5008373.html

[Leetcode] (python): 064-minimum Path Sum