LeetCode-Triangle

iven 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.

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