62. Unique Paths
Medium
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?
Example 1:
Input: m = 3, n = 7 Output: 28
Example 2:
Input: m = 3, n = 2 Output: 3 Explanation: From the top-left corner, there are a total of 3 ways to reach the bottom-right corner: 1. Right -> Down -> Down 2. Down -> Down -> Right 3. Down -> Right -> Down
Example 3:
Input: m = 7, n = 3 Output: 28
Example 4:
Input: m = 3, n = 3 Output: 6
Constraints:
1 <= m, n <= 100
- It's guaranteed that the answer will be less than or equal to
2 * 109
.
1 2 3 4 5 6 7 8 9 10 11 12 | class Solution { public: int uniquePaths(int m, int n) { vector<int> dp(n, 1); for(int i=1; i<m; ++i){ for(int j=1; j<n; ++j){ dp[j] += dp[j-1]; } } return dp[n-1]; } }; |
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