Triangle

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).

class Solution {
public:
    int minimumTotal(vector<vector<int>>& triangle) {
        int m = triangle.size();
        vector<int> help(m,0);
        for(int i=0;i<m;i++){
            int n = triangle[i].size();
            for(int j=n-1;j>=0;j--){
                if(j==0 ){
                    help[j] += triangle[i][j];
                }else if(j==n-1){
                    help[j] = help[j-1]+triangle[i][j];
                }else{
                    help[j] = min(help[j-1],help[j]) + triangle[i][j];
                }
            }
        }
        int miniTotal = 0;
        for(int i=0;i<m;i++){
            if(i==0) miniTotal=help[i];
            else miniTotal = min(miniTotal,help[i]);
        }
        return miniTotal;
    }
};