LeetCode - 20. Valid Parentheses
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20. Valid Parentheses
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Mean:
给定一个括号序列，检查括号是否按顺序匹配.
analyse:
栈结构的基本运用.
Time complexity: O(N)
view code
/** * ----------------------------------------------------------------- * Copyright (c) 2016 crazyacking.All rights reserved. * ----------------------------------------------------------------- * Author: crazyacking * Date : 2016-02-17-16.33 */ #include <queue> #include <cstdio> #include <set> #include <string> #include <stack> #include <cmath> #include <climits> #include <map> #include <cstdlib> #include <iostream> #include <vector> #include <algorithm> #include <cstring> using namespace std;
typedef long long(
LL);
typedef unsigned long long(
ULL);
const double eps(
1e-8);
class Solution { public : bool isValid(
string s)
{ stack < char > sta;
for(
auto p:s)
{ if(p
== '(' || p
== '{' || p
== '[')
sta . push(p);
else if(p
== ')')
{ if(
sta . empty())
return false;
char tp = sta . top();
sta . pop();
if(
tp != '(')
return false;
} else if(p
== '}')
{ if(
sta . empty())
return false;
char tp = sta . top();
sta . pop();
if(
tp != '{')
return false;
} else { if(
sta . empty())
return false;
char tp = sta . top();
sta . pop();
if(
tp != '[')
return false;
} } if(
sta . empty())
return true;
else return false;
} }; int main()
{ Solution solution;
string s;
while(
cin >>s)
{ if(
solution . isValid(s))
cout << "Yes." << endl;
else cout << "No." << endl;
} return 0;
} /* */ 转载地址：http://okanx.baihongyu.com/