Ultraviolet A 10943-how do you add? (Combination number formula + recurrence)

 

 

Ultraviolet A 10943-how do you add? (Combination number formula + recurrence)

 

 

Question:
Given a number N, the number of shard K is decomposed, and the number of combinations can be repeated (n <= 100)


Analysis:
Abstract The question into N identical balls by combining mathematics, put them into k different boxes, and allow the box to be empty.
Then we can use the partition method ------> ans = C (n + M-1, M-1)
Partition Method --> BD
And then according to the nature of the number of combinations can be recursive (this data range is relatively small) ----> C (a, B) = C (A-1, B) + C (A-1, b-1 );
After preprocessing, the corresponding output can be obtained.

 

Ultraviolet A 10943-how do you add? (Combination number formula + recurrence)