Description
Juan is a very gifted programmer, and has a severe case of ACM (he even participated in an ACM world championship a few months ago). Lately, his loved ones are worried about him, because he has found a new exciting problem to exercise his intellectual powers, and he has been speechless for several weeks now. The problem is the determination of the number of different labeled binary trees that can be built using exactlyn different elements.
For example, given one element A, just one binary tree can be formed (usingA as the root of the tree). With two elements, A and B, four different binary trees can be created, as shown in the figure.
If you are able to provide a solution for this problem, Juan will be able to talk again, and his friends and family will be forever grateful.
1 2 10 25 0
1 4 60949324800 75414671852339208296275849248768000000
題意:給你n個點,問能夠構成多少種不同的樹。
解析:卡特蘭數。
AC代碼:
#include#include #define SIZE 200 #define MAXN 302 #define BASE 10000 using namespace std; int Canlan[MAXN][SIZE]; int temp[SIZE]; void A(int n) { memcpy(temp, Canlan[n], sizeof(temp)); int e = 0; for(int fac = n; fac>0; --fac) { for(int i = SIZE-1, remain = 0; i>=0; --i) { e = temp[i] * fac + remain; temp[i] = e % BASE; remain = e / BASE; } } memcpy(Canlan[n], temp, sizeof(int)*SIZE); } void multiply(int elem) { for(int i=SIZE-1, remain = 0; i >= 0; --i) { remain = temp[i] * elem + remain; temp[i] = remain % BASE; remain = remain / BASE; } return; } void divide(int elem) { int i; for(i=0; i