2017 Multi-University Training Contest

Two strings

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 520    Accepted Submission(s): 195

Problem Description

Giving two strings and you should judge if they are matched.
The first string contains lowercase letters and uppercase letters.
The second string contains lowercase letters, uppercase letters, and special symbols: “.” and “*”.
. can match any letter, and * means the front character can appear any times. For example, “a.b” can match “acb” or “abb”, “a*” can match “a”, “aa” and even empty string. ( “*” will not appear in the front of the string, and there will not be two consecutive “*”.

 

Input

The first line contains an integer T implying the number of test cases. (T≤15)
For each test case, there are two lines implying the two strings (The length of the two strings is less than 2500).

 

Output

For each test case, print “yes” if the two strings are matched, otherwise print “no”.

 

Sample Input

3aaa*abba.*abbaab

 

Sample Output

yesyesno

 

题目大意：问给出的正则表达式能否匹配文本

解题思路：c++regex   注意.*不能匹配ab

这个真不会呀啊啊啊啊啊啊 = =

#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <string>#include <regex>using namespace std;const int MAXN = 2600;string s, p;int main(){    int T;    cin >> T;    while (T--)    {        cin >> s >> p;        string s1 = ".*";        string s2 = "(a*|b*|c*|d*|e*|f*|g*|h*|i*|j*|k*|l*|m*|n*|o*|p*|q*|r*|s*|t*|u*|v*|w*|x*|y*|z*"                    "|A*|B*|C*|D*|E*|F*|G*|H*|I*|J*|K*|L*|M*|N*|O*|P*|Q*|R*|S*|T*|U*|V*|W*|X*|Y*|Z*)";        auto pos = p.find(s1);        while (pos != string::npos)        {            p.replace(pos, 2, s2);            pos = p.find(s1, pos + 157);        }        regex pat(p);        if (regex_match(s, pat))        {            cout << "yes" << endl;        }        else        {            cout << "no" << endl;        }    }    return 0;}