int minimumTotal(vector<vector<int>>& triangle) {

int n = triangle.size();

int ret = 0;

if (n == 0) {

return ret;

} else {

ret = 2147483647;

}

vector<int> pre = triangle[0];

for (int i = 1; i < n; ++i) {

vector<int> tmp;

vector<int> now = triangle[i];

tmp.push_back(pre[0] + now[0]);

for (int j = 1; j < pre.size(); ++j) {

tmp.push_back(min(pre[j-1], pre[j]) + now[j]);

}

tmp.push_back(pre[pre.size()-1] + now[now.size()-1]);

pre = tmp;

}

for (int i = 0; i < pre.size(); ++i) {

ret = min(ret, pre[i]);

}

return ret;

}