Glede na niz nizov (vse male črke) je naloga, da jih združimo tako, da so vsi nizi v skupini zamaknjene različice drug drugega.
Dve struni s1 in s2 se imenujejo premaknjeni, če so izpolnjeni naslednji pogoji:
- s1.dolžina je enako s2.dolžina
- s1[i] je enako s2[i] + m za vse 1<= i <= s1.length for a konstantna celo število m. Upoštevajte, da je premik cikličen, to je, če s2[i] + m > 'z', potem začnite od 'a' ali če s2[i] + m< 'a' then start from 'z'.
Primeri:
Vnos: arr[] = ['acd' 'dfg' 'wyz' 'yab' 'mop' 'bdfh' 'a' 'x' 'moqs']
Izhod: [ ['acd' 'dfg' 'wyz' 'yab' 'mop'] ['bdfh' 'moqs'] ['a' 'x'] ]
Pojasnilo: Vsi premaknjeni nizi so združeni.
Vnos: arr = ['geek' 'za' 'geeks']
Izhod: [['za'] ['geek'] ['geeks']]
Pristop: Uporaba zgoščenega zemljevida
C++Ideja je ustvariti edinstveno hash za vsako skupino po normalizacijo strune. Tukaj normalizacijo pomeni, da je prvi znak vsakega niza enak 'a' z izračunom zahtevanega izmene in jo enotno uporabi za vse znake v ciklična moda .
Primer: s = 'dca' premiki = 'd' - 'a' = 3
normalizirani znaki: 'd' - 3 = 'a' 'c' - 3 = 'z' in 'a' - 3 = 'x'
normalizirani niz = 'azx'The normaliziran niz (hash) predstavlja prestavni vzorec tako, da imajo nizi z enakim vzorcem enak hash. Za sledenje teh zgoščenih vrednosti in njihovo preslikavo v ustrezne skupine uporabljamo hash zemljevid. Za vsak niz izračunamo zgoščeno vrednost in jo uporabimo za ustvarjanje nove skupine ali dodajanje niza obstoječi skupini v enem samem prehodu.
// C++ program to print groups of shifted strings // together using Hash Map #include
// Java program to print groups of shifted strings // together using Hash Map import java.util.*; class GfG { // Function to generate hash by shifting and equating the // first character static String getHash(String s) { // Calculate the shift needed to normalize the string int shifts = s.charAt(0) - 'a'; char[] chars = s.toCharArray(); for (int i = 0; i < chars.length; i++) { // Adjust each character by the shift chars[i] = (char) (chars[i] - shifts); // Wrap around if the character goes below 'a' if (chars[i] < 'a') chars[i] += 26; } return new String(chars); } // Function to group shifted strings together static ArrayList<ArrayList<String>> groupShiftedString(String[] arr) { ArrayList<ArrayList<String>> res = new ArrayList<>(); // Maps hash to index in result HashMap<String Integer> mp = new HashMap<>(); for (String s : arr) { // Generate hash representing the shift pattern String hash = getHash(s); // If new hash create a new group if (!mp.containsKey(hash)) { mp.put(hash res.size()); res.add(new ArrayList<>()); } // Add string to its group res.get(mp.get(hash)).add(s); } return res; } public static void main(String[] args) { String[] arr = {'acd' 'dfg' 'wyz' 'yab' 'mop' 'bdfh' 'a' 'x' 'moqs'}; ArrayList<ArrayList<String>> groups = groupShiftedString(arr); for (ArrayList<String> group : groups) { for (String s : group) { System.out.print(s + ' '); } System.out.println(); } } }
# Python program to print groups of shifted strings # together using Hash Map # Function to generate hash by shifting and equating the first character def getHash(s): # Calculate the shift needed to normalize the string shifts = ord(s[0]) - ord('a') hashVal = [] for ch in s: # Adjust each character by the shift newCh = chr(ord(ch) - shifts) # Wrap around if the character goes below 'a' if newCh < 'a': newCh = chr(ord(newCh) + 26) hashVal.append(newCh) return ''.join(hashVal) # Function to group shifted strings together def groupShiftedString(arr): res = [] # Maps hash to index in result mp = {} for s in arr: # Generate hash representing the shift pattern hashVal = getHash(s) # If new hash create a new group if hashVal not in mp: mp[hashVal] = len(res) res.append([]) # Add string to its group res[mp[hashVal]].append(s) return res if __name__ == '__main__': arr = ['acd' 'dfg' 'wyz' 'yab' 'mop' 'bdfh' 'a' 'x' 'moqs'] groups = groupShiftedString(arr) for group in groups: print(' '.join(group))
// C# program to print groups of shifted strings // together using Hash Map using System; using System.Collections.Generic; class GfG { // Function to generate hash by shifting and equating the first character static string getHash(string s) { // Calculate the shift needed to normalize the string int shifts = s[0] - 'a'; char[] chars = s.ToCharArray(); for (int i = 0; i < chars.Length; i++) { // Adjust each character by the shift chars[i] = (char)(chars[i] - shifts); // Wrap around if the character goes below 'a' if (chars[i] < 'a') chars[i] += (char)26; } return new string(chars); } // Function to group shifted strings together static List<List<string>> groupShiftedString(string[] arr) { List<List<string>> res = new List<List<string>>(); // Maps hash to index in result Dictionary<string int> mp = new Dictionary<string int>(); foreach (string s in arr) { // Generate hash representing the shift pattern string hash = getHash(s); // If new hash create a new group if (!mp.ContainsKey(hash)) { mp[hash] = res.Count; res.Add(new List<string>()); } // Add string to its group res[mp[hash]].Add(s); } return res; } static void Main(string[] args) { string[] arr = { 'acd' 'dfg' 'wyz' 'yab' 'mop' 'bdfh' 'a' 'x' 'moqs' }; var groups = groupShiftedString(arr); foreach (var group in groups) { Console.WriteLine(string.Join(' ' group)); } } }
// JavaScript program to print groups of shifted strings // together using Hash Map // Function to generate hash by shifting and equating the first character function getHash(s) { // Calculate the shift needed to normalize the string const shifts = s.charCodeAt(0) - 'a'.charCodeAt(0); let chars = []; for (let ch of s) { // Adjust each character by the shift let newChar = String.fromCharCode(ch.charCodeAt(0) - shifts); // Wrap around if the character goes below 'a' if (newChar < 'a') newChar = String.fromCharCode(newChar.charCodeAt(0) + 26); chars.push(newChar); } return chars.join(''); } // Function to group shifted strings together function groupShiftedString(arr) { const res = []; // Maps hash to index in result const mp = new Map(); for (let s of arr) { // Generate hash representing the shift pattern const hash = getHash(s); // If new hash create a new group if (!mp.has(hash)) { mp.set(hash res.length); res.push([]); } // Add string to its group res[mp.get(hash)].push(s); } return res; } // Driver Code const arr = ['acd' 'dfg' 'wyz' 'yab' 'mop' 'bdfh' 'a' 'x' 'moqs']; const groups = groupShiftedString(arr); groups.forEach(group => console.log(group.join(' ')));
Izhod
acd dfg wyz yab mop bdfh moqs a x
Časovna zapletenost: O(n*k), kjer je n dolžina matrike nizov in k največja dolžina niza v matriki nizov.
Pomožni prostor: O(n*k) v najslabšem primeru lahko ustvarimo n različnih zgoščenih nizov za vsak vhodni niz. Tako smo dobili n različnih vnosov v razpršenem zemljevidu, vsak z dolžino k ali manj.