( 12 * 1 & lt； 18 can't climb to the top, the number of steps to climb the first step can't exceed 12, 2*9= 18, and the number of steps to climb the second step can't exceed 9, so let's limit it in a wide range. )
The number of steps (series) to climb the first step and the number of steps (series) to climb the second step.
12( 12) 0(0)
1 1( 1 1) 1(2)
10( 10) 2(4)
9 (9) 3(6)
8(8) 4(8)
7 (7) 5( 10)
6(6) 6( 12) is the only one that meets the requirements.
5(5) 7( 14)
4(4) 8( 16)
3(3) 9( 18)
So the number of steps to climb the first step and the second step is six. After understanding the principle, you can judge which one fits, and judging this is not the point. )
How to combine the order of climbing the first step and the second step to form different walking modes can be represented by drawing a stem-leaf diagram, in which climbing the first step is represented by 1 and the second step is represented by 2. (There is a high school in the picture)
Two cases in the first step, four cases in the second step, eight cases in the third step and 16 cases in the fourth step.
And so on to step 6, a total of 64 cases.
Please ask questions if you don't understand!
Hope to adopt! !