75 lines
2.2 KiB
C++
75 lines
2.2 KiB
C++
// Source : https://leetcode.com/problems/word-pattern/
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// Author : Hao Chen
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// Date : 2015-10-22
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/***************************************************************************************
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*
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* Given a pattern and a string str, find if str follows the same pattern.
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* Here follow means a full match, such that there is a bijection between a letter in
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* pattern and a non-empty word in str.
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*
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* Examples:
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*
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* pattern = "abba", str = "dog cat cat dog" should return true.
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* pattern = "abba", str = "dog cat cat fish" should return false.
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* pattern = "aaaa", str = "dog cat cat dog" should return false.
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* pattern = "abba", str = "dog dog dog dog" should return false.
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*
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* Notes:
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* You may assume pattern contains only lowercase letters, and str contains lowercase
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* letters separated by a single space.
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*
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* Credits:Special thanks to @minglotus6 for adding this problem and creating all test
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* cases.
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*
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***************************************************************************************/
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class Solution {
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private::
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vector<string> split(string str, char delimiter) {
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vector<string> internal;
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stringstream ss(str); // Turn the string into a stream.
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string tok;
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while(getline(ss, tok, delimiter)) {
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internal.push_back(tok);
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}
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return internal;
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}
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public:
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bool wordPattern(string pattern, string str) {
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unordered_map<char, string> dict_pattern;
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unordered_map<string, char> dict_string;
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int len = pattern.size();
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vector<string> strs = split(str, ' ');
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if (len != strs.size()) return false;
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for(int i=0; i<len; i++) {
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char& ch = pattern[i];
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string& s = strs[i];
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if ( dict_pattern.find(ch) == dict_pattern.end() ) {
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dict_pattern[ch] = s;
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}
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if ( dict_string.find(s) == dict_string.end() ) {
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dict_string[s] = ch;
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}
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if ( dict_pattern[ch] != s || dict_string[s] != ch ) {
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return false;
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}
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}
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return true;
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}
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};
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