Question

求解答下面这道题的完整代码（用C++），目前不太会用map，所以希望能不用就不用map，谢谢谢谢

求解答下面这道题的完整代码（用C++），目前不太会用map，所以希望能不用就不用map，谢谢谢谢word pattern
Given a pattern and a string str, find if str follows the same pattern.

Examples:

pattern = "abba", str = "dog cat cat dog" should return true.
pattern = "abba", str = "dog cat cat fish" should return false.
pattern = "aaaa", str = "dog cat cat dog" should return false.
pattern = "abba", str = "dog dog dog dog" should return false.
Notes:

Both pattern and str contains only lowercase alphabetical letters.
Both pattern and str do not have leading or trailing spaces.
Each word in str is separated by a single space.
Each letter in pattern must map to a word with length that is at least 1.

Answer 1

#include <iostream>
#include <string>
#include <sstream>
#include <vector>

bool match(const std::string &pattern, const std::string &str)
{
    bool result = true;
    std::string word;
    std::vector <std::string> word_list;
    size_t size = pattern.size();
    word_list.reserve(size);
    
    std::istringstream read(str);
    while (read >> word) word_list.push_back(word);
    
#if DEBUG
    assert(size == word_list.size());
#endif

    for (int i = 0; i < size; i ++)
    {
        for (int j = i + 1; j < size; j ++)
        {
            bool pattern_match = pattern[i] == pattern[j];
            bool word_match = word_list[i] == word_list[j];
            if (pattern_match != word_match)
            {
                result = false;
            }
        }
    }
    
    return result;
}

void checkAndPrintResult(const std::string &pattern, const std::string &str)
{
    std::cout << "pattern = \"" << pattern << "\", str = \"" << str << "\" should return "
        << (match(pattern, str) ? "true" : "false") << ".\n";
}

int main()
{
    checkAndPrintResult("abba", "dog cat cat dog");
    checkAndPrintResult("abba", "dog cat cat fish");
    checkAndPrintResult("aaaa", "dog cat cat dog");
    checkAndPrintResult("abba", "dog dog dog dog");
    
    return 0;
}

1. 图省事的做法，时间复杂度 O((pattern.size()^2), 不是很优化，但您未在描述中提出数据范围等。

2. 未使用 map