初始化（0,0）

class Solution {public:    int uniquePaths(int m, int n) {        vector
     
      
       > result(m,vector
       
        (n));        result[0][0] = 1;        for(int i = 0;i < m;i++){            for(int j = 0;j < n;j++){                if(i == 0 && j == 0)                    continue;                if(i != 0 && j != 0){                    result[i][j] = result[i][j-1] + result[i-1][j];                }                else if(i == 0)                    result[i][j] = result[i][j-1];                else                    result[i][j] = result[i-1][j];            }        }        return result[m-1][n-1];    }};
       
      
     

 初始化第一行第一列

class Solution {public:    int uniquePaths(int m, int n) {        vector
     
      
       > result(m,vector
       
        (n));        result[0][0] = 1;        for(int i = 1;i < m;i++)            result[i][0] = 1;        for(int j = 1;j < n;j++)            result[0][j] = 1;        for(int i = 1;i < m;i++){            for(int j = 1;j < n;j++){                result[i][j] = result[i-1][j] + result[i][j-1];            }        }        return result[m-1][n-1];    }};