题目

word-pattern

算法

* 哈希

* 两个哈希

代码

* 哈希

class Solution {
public:
    bool wordPattern(string pattern, string str) {
        unordered_map<char, string> m;
        istringstream in(str);
        int i = 0;
        for (string word; in >> word; ++i) {
            if (m.find(pattern[i]) != m.end()) {
                if (m[pattern[i]] != word) return false;
            } else {
                for (unordered_map<char, string>::iterator it = m.begin(); it != m.end(); ++it) {
                    if (it->second == word) return false;
                }
                m[pattern[i]] = word;
            }
        }
        return i == pattern.size();
    }
};

* 两个哈希

class Solution {
public:
    bool wordPattern(string pattern, string str) {
        unordered_map<char, int> m1;
        unordered_map<string, int> m2;
        istringstream in(str);
        int i = 0;
        for (string word; in >> word; ++i) {
            if (m1.find(pattern[i]) != m1.end() || m2.find(word) != m2.end()) {
                if (m1[pattern[i]] != m2[word]) return false;
            } else {
                m1[pattern[i]] = m2[word] = i + 1;
            }
        }
        return i == pattern.size();
    }
};