Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.
For example, given n = 3, a solution set is:
"((()))", "(()())", "(())()", "()(())", "()()()"
给定n对括号，输出所有可行的括号组合字符串。所谓合法，就是可以Valid Parentheses方法评判得到true
class Solution {
public:
bool isPair(char left, char right){
if(left==‘(‘&&right==‘)‘)return true;
return false;
}
void combination(vector<string>&result, stack<char>st, string comb, int leftPareNum, int rightPareNum){
if(leftPareNum==0&&rightPareNum==0){
result.push_back(comb);
return;
}
if(st.empty()){
//如果为空则左括号入栈
if(leftPareNum>0){
st.push(‘(‘);
combination(result,st,comb+"(",leftPareNum-1,rightPareNum);
}
}
else{
char stTop=st.top();
if(stTop==‘(‘){
if(leftPareNum>0){
st.push(‘(‘);
combination(result, st, comb+"(",leftPareNum-1,rightPareNum);
st.pop();
}
if(rightPareNum>0){
st.pop();
combination(result,st, comb+")",leftPareNum,rightPareNum-1);
}
}
else{
//栈顶为右括号，只能压入左括号
if(leftPareNum>0){
st.push(‘(‘);
combination(result,st,comb+"(",leftPareNum-1,rightPareNum);
}
}
}
}
vector<string> generateParenthesis(int n) {
vector<string>result;
stack<char>st;
combination(result,st,"",n,n);
return result;
}
};LeetCode: Generate Parentheses [021],布布扣,bubuko.com
LeetCode: Generate Parentheses [021]
原文地址：http://blog.csdn.net/harryhuang1990/article/details/26007139
