triangle

class Solution {
public:
    int minimumTotal(vector<vector<int> > &a) {
        for(int i=a.size()-2;i>=0;i--)
            for(int j=0;j<i+1;j++)
                a[i][j]+=min(a[i+1][j],a[i+1][j+1]);
        return a[0][0];
    }
};