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) {
        map<int,int> sum,tempSum;
        for(int i=0;i<triangle.size();++i){
            for(int j=0;j<triangle[i].size();++j){
                if(i==0){
                    sum[j]=triangle[i][j];
                }else{
                    if(j==0){
                        sum[j]=tempSum[j]+triangle[i][j];
                    }else if(j==triangle[i].size()-1){
                        sum[j]=tempSum[j-1]+triangle[i][j];
                    }else{
                        int a=tempSum[j-1]+triangle[i][j];
                        int b=tempSum[j]+triangle[i][j];
                        sum[j]=min(a,b);
                    }
                }
            }
            tempSum=sum;
        }
        int min =(unsigned int)(-1) >>1;
        for(map<int,int>::iterator iter=sum.begin();iter!=sum.end();++iter){
            if(iter->second < min) 
                 min=iter->second;
        }
        return min;
    }

};

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