RSA算法 :首先, 找出三個數, p, q, r, 其中 p, q 是兩個相異的質數, r 是與 (p-1)(q-1) 互質的數...... p, q, r 這三個數便是 person_key，接著, 找出 m, 使得 r^m == 1 mod (p-1)(q-1)..... 這個 m 一定存在, 因為 r 與 (p-1)(q-1) 互質, 用輾轉相除法就可以得到了..... 再來, 計算 n = pq....... m, n 這兩個數便是 public_key ，編碼過程是, 若資料為 a, 將其看成是一個大整數, 假設 a < n.... 如果 a >= n 的話, 就將 a 表成 s 進位 (s
The government of a small but important country has decided that the alphabet needs to be streamlined and reordered. Uppercase letters will be eliminated. They will issue a royal decree in the form of a String of B and A characters. The first character in the decree specifies whether a must come ( B )Before b in the new alphabet or ( A )After b . The second character determines the relative placement of b and c , etc. So, for example, "BAA" means that a must come Before b , b must come After c , and c must come After d .
Any letters beyond these requirements are to be excluded, so if the decree specifies k comparisons then the new alphabet will contain the first k+1 lowercase letters of the current alphabet.
Create a class Alphabet that contains the method choices that takes the decree as input and returns the number of possible new alphabets that conform to the decree. If more than 1,000,000,000 are possible, return -1.
Definition
光學設計軟件zemax源碼：
This DLL models an nular aspheric
surface as described in:
"Annular surfaces in annular field systems"
By Jose M. Sasian
Opt. eng. 36 (12) P 3401-3401 December 1997
This surface is essentially an odd aspheric surface with an offset in the aspheric terms.
The sag is given by:
Z = (c*r*r) / (1+(1-((1+k)*c*c*r*r))^ 1/2 ) + a*(r-q)^2 + b*(r-q)^3 + c*(r-q)^4 + ...
Note the terms a, b, c, ... have units of length to the -1, -2, -3, ... power.
