帶棧和隊列的字符串迴文（C++）

Question

這個編譯良好，並且沒有空格，但是一旦我在其中放入空格，它或者告訴我它不是迴文或超時。任何幫助將不勝感激！

int main() 
{ 
    queue<char> q; 
    stack<char> s; 
    string the_string; 
    int mismatches = 0; 
    cout << "Enter a line and I will see if it's a palindrome:" << endl; 
    cin >> the_string; 

    int i = 0; 
    while (cin.peek() != '\n') 
    { 
     cin >> the_string[i]; 
     if (isalpha(the_string[i])) 
     { 
      q.push(toupper(the_string[i])); 
      s.push(toupper(the_string[i])); 
     } 
     i++; 
    } 

    while ((!q.empty()) && (!s.empty())) 
    { 
     if (q.front() != s.top()) 
      ++mismatches; 

     q.pop(); 
     s.pop(); 
    } 

    if (mismatches == 0) 
     cout << "This is a palindrome" << endl; 
    else 
     cout << "This is not a palindrome" << endl; 

    system("pause"); 
    return EXIT_SUCCESS; 
} 

Answer 1

爲什麼這麼複雜？

你可以簡單地做：

#include <string> 
#include <algorithm> 

bool is_palindrome(std::string const& s) 
{ 
    return std::equal(s.begin(), s.begin()+s.length()/2, s.rbegin()); 
} 

Answer 2

首先行

cin >> the_string; 

沒有得到一整行。其次，在調試你的算法時會打印出大量的信息。例如，如果您添加行

cout << "You entered: '" << the_string << "'" << endl; 

您可以很容易地看到您正在測試的字符串。

Answer 3

我得到了這個解決方案工作得很好。

int main() 
{ 
    queue<char> q; 
    stack<char> s; 
    string the_string; 
    int mismatches = 0; 

    cout << "Enter a line and I will see if it's a palindrome:" << endl; 
    int i = 0; 

    while (cin.peek() != '\n') 
    { 
     cin >> the_string[i]; 
     if (isalpha(the_string[i])) 
     { 
      q.push(toupper(the_string[i])); 
      s.push(toupper(the_string[i])); 
    } 
    i++; 
    } 

    while ((!q.empty()) && (!s.empty())) 
    { 
     if (q.front() != s.top()) 
      ++mismatches; 

     q.pop(); 
     s.pop(); 
    } 

if (mismatches == 0) 
    cout << "This is a palindrome" << endl; 
else 
    cout << "This is not a palindrome" << endl; 

    system("pause"); 
    return EXIT_SUCCESS; 
} 

Answer 4

void main() 
{ 
    queue<char> q; 
    stack<char> s; 
    char letter; 
    int mismatches = 0; 


    cout << "Enter a word and I will see if it's a palindrome:" << endl; 
    cin >> letter; 
    q.push(letter); 
    s.push(letter); 

    int i = 0; 
    while (cin.peek() != '\n') 
    { 
     cin >> letter; 
     if (isalpha(letter)) 
     { 
      q.push(letter); 
      s.push(letter); 
     } 
     i++; 
    } 

    while ((!q.empty()) && (!s.empty())) 
    { 
     if (q.front() != s.top()) 
      ++mismatches; 

     q.pop(); 
     s.pop(); 
    } 

    if (mismatches == 0) 
    { 
     cout << "This is a palindrome" << endl; 
    } 
    else 
    { 
     cout << "This is not a palindrome" << endl; 
    } 
    cout << endl; 
    cout << "Homework done!" << endl; 
    cout << "You are Welcome!" << endl; 
    system("pause"); 

}