标签：logs bin color style pre == blog arc for
这里需要总结规律：
f(0)=f(1)=1;
f(2)=f(0)*f(1) + f(1)*f(0)
f(3)=f(0)*f(2) + f(1)*f(1) + f(2)*f(0)
class Solution { public: int numTrees(int n) { if(n == 0) return 1; if(n == 1) return 1; vector<int> num(n+1,0); num[0] = 1; num[1] = 1; for(int i=2; i<n+1; ++i) { for(int j=0; j<i; ++j) num[i] += num[j]*num[i-1-j]; } return num[n]; } };
标签：logs bin color style pre == blog arc for
原文地址：http://www.cnblogs.com/chengyuz/p/6718377.html
