Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below.
For example, given the following triangle
[ [2], [3,4], [6,5,7], [4,1,8,3] ]
The minimum path sum from top to bottom is11(i.e., 2 + 3 + 5 + 1 = 11).
Note: Bonus point if you are able to do this using only O(n) extra space, where n is the total number of rows in the triangle.
C++
class Solution { public: int minimumTotal(vector<vector<int> > &triangle) { int n = triangle.size(); vector<int> dp(triangle.back()); for (int i = n - 2; i >= 0; --i) for (int j = 0; j <= i; ++j) dp[j] = triangle[i][j] + min(dp[j],dp[j+1]); return dp[0]; } int minimumTotal2(vector<vector<int>>& triangle){ int len = triangle.size(); vector<int> dp(len,0); for(int i = len - 1; i >= 0; --i){ for(int j = 0; j <= i; ++j){ if(i == len - 1) dp[j] = triangle[i][j]; else dp[j] = triangle[i][j] + min(dp[j],dp[j+1]); } } return dp[0]; } };
转载于:https://www.cnblogs.com/vercont/p/10210243.html
