UVa 673 Parentheses Balance -SilverN

You are given a string consisting of parentheses () and []. A string of this type is said to be correct:

(a)

if it is the empty string

(b)

if A and B are correct, AB is correct,

(c)

if A is correct, (A) and [A] is correct.

Write a program that takes a sequence of strings of this type and check their correctness. Your program can assume that the maximum string length is 128.

 

Input 

The file contains a positive integer n and a sequence of n strings of parentheses () and [], one string a line.

 

Output 

A sequence of Yes or No on the output file.

 

Sample Input 

3([])(([()])))([()[]()])()

Sample Output 

YesNoYes





用栈模拟匹配括号

 1 /*UVa 673 Parentheses Balance*/ 2 #include<iostream> 3 #include<algorithm> 4 #include<cmath> 5 #include<cstring> 6 #include<stack> 7 using namespace std; 8 char c[500]; 9 int n;10 int pd(char q,char e){//匹配 11     if(q=='(' && e==')')return 1;12     if(q=='[' && e==']')return 1;13     return 0;14 }15 int main(){16     scanf("%d\n",&n);17     while(n--){18         gets(c);//因为可能读入空串，所以用gets 19         if(strcmp(c,"\n")==0){//空串合法 20             printf("Yes");21             continue;22         }23         int flag=0;24         stack<char>st;25         int L=strlen(c);26         for(int i=0;i<L;i++){27             if(c[i]=='(' || c[i]=='[') st.push(c[i]);//左括号入栈 28             else{//右括号处理 29                 if(st.empty()){30                     flag=1;31                     break;32                 }33                 if(pd(st.top(),c[i])==1) st.pop();34                 else{35                     flag=1;36                     break;37                     }38             }39         }40         if(flag==1 || !st.empty())printf("No\n");41         else printf("Yes\n");42     }43     return 0;44 }