Leetcode's "Dynamic Planning": Triangle

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Title Requirements:

Given a triangle, find the minimum path sum from top to bottom. Each step of the move to adjacent numbers on the row below.

For example, given the following triangle

 1  [  [2  ],  3  [3 , 4  ],  4  [6 , 5 , 7  ],  5  [1 , 8 , 3   6 ] 

The minimum path sum from top to bottom 11 is (i.e., 2 + 3 + 5 + 1 = 11).

Note:
Bonus Point If-able to does this using only O(n) extra space, where n is the total number of rows in the triangle.

The specific code is as follows:

1 classSolution {2  Public:3     intMinimumtotal (vector<vector<int> > &triangle) {4         introws =triangle.size ();5         if(Rows = =0)6             return 0;7         8         int* DP =New int[rows];9         intSzoflastrow = Triangle[rows-1].size ();Ten          for(inti =0; i < Szoflastrow; i++) OneDp[i] = triangle[rows-1][i]; A          -          for(inti = Rows-2; I >-1; i--) -         { the             intcols =triangle[i].size (); -              for(intj =0; J < cols; J + +) -DP[J] = triangle[i][j] + min (dp[j], dp[j +1]); -         } +          -         returndp[0]; +     } A};

View Code

The most central areas of this program are:

1]);

The diagram can be expressed as follows:

　　

An example of this is:

　　

It is important to note that the only change in this example is dp[0],dp[1] and it has not changed.

Leetcode's "Dynamic Planning": Triangle