L丶K丶的博客

There are numbers in each grid in the picture, which stand for the number of unique paths from Start to the grid. Observing the picture, we can easily find that, for any i,j>0, dp[i][j]=dp[i-

I used the data structure "Stack" here, which is convenient to solve this problem. When the parenthesis is a left parenthesis, I push it into the stack. And when the parenthesis is a right par

When seeing this problem, which let us find something in each tree row, I thought I could solve this problem by using "Level-order Traversal". The code is as follows. The Runti