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 is 11 (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.
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思路：
从下往上dp。
c++ code:
class Solution {
public:
int minimumTotal(vector<vector<int>>& triangle) {
int n = triangle.size();
vector<int> dp(triangle[n-1]);
for(int layer = n-2;layer >= 0;layer--) {
for(int i=0;i<triangle[layer].size();i++) {
dp[i] = min(dp[i], dp[i+1]) + triangle[layer][i];
}
}
return dp[0];
}
};原文：http://blog.csdn.net/itismelzp/article/details/51628994