A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).
The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).
How many possible unique paths are there?
Above is a 3 x 7 grid. How many possible unique paths are there?
Note: m and n will be at most 100.
简单dp
;
- 建立
dp
数组,dp[i][j]
代表到达(i,j)
位置的方法。 - 那么
dp[i][j] = dp[i-1][j] + dp[i][j-1]
, 就很显而易见了。
class Solution {
public:
int uniquePaths(int m, int n) {
vector<vector<unsigned int>>dp(m+1, vector<unsigned int>(n+1, 0));
dp[1][1] = 1;
for(int i=1; i<m+1; ++ i)
{
for(int j=1; j<n+1; ++ j)
{
if(i == 1 && j == 1)
continue;
dp[i][j] = dp[i-1][j] + dp[i][j-1];
}
}
return dp[m][n];
}
};