【微软谷歌面试100题--【46】N对括号可以有多少种匹配排列方式
题46

N对括号可以有多少种匹配排列方式？比如两对括号可以有两种：（）（）和（（））

主要的思想还是递归！

#include "stdafx.h"#include<iostream>//#include<cassert>#include <vector>using namespace std ;void Print(vector<char> v){for (vector<char>::iterator beg=v.begin();beg!=v.end();++beg)cout<<*beg<<" ";cout<<endl;}void MatchNums(int nSize,int nLen,vector<char> &v){int nLeftBrackets=0;int nRightBrackets=0;for (vector<char>::iterator beg=v.begin();beg!=v.end();++beg){if(*beg=='(')nLeftBrackets++;elsenRightBrackets++;if(nRightBrackets>nLeftBrackets)return;if(nLeftBrackets+nRightBrackets==nSize&&nLeftBrackets==nRightBrackets)Print(v);}if (nLen>0){v.push_back('(');MatchNums(nSize,nLen-1,v);v.pop_back();v.push_back(')');MatchNums(nSize,nLen-1,v);v.pop_back();}}int main(){vector <char> v;int n=6;MatchNums(n,n,v);return 0;}