1.刚开始result的初始化写的是vector<vector<int>> result,然后再去对result[0][0] = triangle[0][0]赋值，一直报错。老问题了！

2.多维vector的初始化：

vector<vector<int>> result(height,vector<int>(width))

class Solution {public:    int minimumTotal(vector
     
      
       >& triangle) {        int height = triangle.size();        if(height <= 0)            return 0;        if(height == 1)            return triangle[0][0];        int width = triangle[height-1].size();        vector
       
        
         > result(height,vector
         
          (width));        result[0][0] = triangle[0][0];        for(int i = 1;i < height;i++){            width = triangle[i].size();            for(int j = 0;j < width;j++){                if(j !=0 && j != (width-1)){                    result[i][j] = min(result[i-1][j] + triangle[i][j],result[i-1][j-1] + triangle[i][j]);                }                else if(j == 0)                    result[i][j] = result[i-1][j] + triangle[i][j];                else                    result[i][j] = result[i-1][j-1] + triangle[i][j];            }        }        int min_num = 0x7fffffff;        for(int i = 0;i < triangle[height-1].size();i++){            if(min_num > result[height-1][i])                min_num = result[height-1][i];        }        return min_num;    }};
         
        
       
      
     

 简化版

class Solution {public:    int minimumTotal(vector
     
      
       >& triangle) {        int length = triangle.size();        vector
       
        
         > result(length,vector
         
          (length));        result[0][0] = triangle[0][0];        for(int i = 1;i < length;i++){            for(int j = 0;j <= i;j++){                if(j == 0)                    result[i][j] = result[i-1][j] + triangle[i][j];                else if(j == i)                    result[i][j] = result[i-1][j-1] + triangle[i][j];                else                    result[i][j] = min(result[i-1][j],result[i-1][j-1]) + triangle[i][j];            }        }        int min_num = 0x7FFFFFFF;        for(int i = 0;i < length;i++){            if(result[length-1][i] < min_num)                min_num = result[length-1][i];        }        return min_num;    }};