Triangle

class Solution {public:    int minimumTotal(vector<vector<int> > &triangle) {        vector<int> preRow(triangle.size(),0);vector<int> curRow(triangle.size(),0);int minSum=INT_MAX;for(size_t i=0;i<triangle.size();i++){for(size_t j=0;j<=i;j++){if(j==0){curRow[j]=preRow[0]+triangle[i][j];minSum=curRow[j];}else if(j==i){curRow[j]=preRow[i-1]+triangle[i][j];}else{curRow[j]=min(preRow[j-1]+triangle[i][j],preRow[j]+triangle[i][j]);}minSum=min(curRow[j],minSum);}for(size_t p=0;p!=triangle.size();p++){preRow[p]=curRow[p];}}return minSum;    }};