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).

Triangle.cpp

class Solution {
public:
    int minimumTotal(vector<vector<int> > &triangle) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        
        vector<int> second = triangle[triangle.size() - 1];
        
        for(int i = triangle.size() - 2; i >= 0; --i) {
            vector<int> first = triangle[i];
            
            for(int j = 0; j < first.size(); ++j) {
                first[j] += min(second[j], second[j + 1]);
            }
            
            second = first;
        }
        
        return second[0];
    }
};