64. Minimum Path Sum

寻找从左上角到右下角的最短路劲：F(i,j)=min{arr(i,j)+f(i-1,j),arr(i,j)+f(i,j-1)}

class Solution {
public:
    int minPathSum(vector<vector<int>>& grid) {
        for(int i=0;i<grid.size();i++)
    	{
    		for(int j=0;j<grid[0].size();j++)
    		{

    			if(i==0&&j==0)
    				continue;
                
    			if(i==0&&j>0)
    			{
    				grid[i][j]+=grid[i][j-1];
    				continue;
    			}

    			if(i>0&&j==0)
    			{
    				grid[i][j]+=grid[i-1][j];
    				continue;
    			}

	   			int left=INT_MAX,right=INT_MAX;
    			left=grid[i][j]+grid[i][j-1];   						
    			right=grid[i][j]+grid[i-1][j];
    			grid[i][j]=min(left,right);
    		}
    	}
        return grid[grid.size()-1][grid[0].size()-1];
    }
};