b***k 发帖数: 2673 | 1 ☆─────────────────────────────────────☆
jejune (孑孓) 于 (Fri Apr 25 13:27:45 2008) 提到:
a 10x6 grid (or m x n), we mark the left bottom corner as (0,0), and right
top corner as (10,6) ( or (m,n)). start from (0,0), each step you can move
one grid toward right or up, and ended at (10,6) (or (m,n)).
1. (easy one) how many possible different paths?
2. if we require in each grid (x,y) on the path, (x>=y), how many possible
different paths to get to (m,n)?
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