Group Anagrams: hash, sort string.

Author: DeanChensj

Medium/049_Group-Anagrams.cpp

@@ -0,0 +1,32 @@
+#include "../Header.h"
+
+using namespace std;
+vector<vector<string>> groupAnagrams(vector<string>& strs) {
+    vector<vector<string> > res;
+    sort(strs.begin(), strs.end());
+    
+    int cnt = 0;
+    //            hash_code   index
+    unordered_map<string, int> hash;
+    for (int i = 0; i < strs.size(); i++) {
+        int *tmp = new int[26];
+        memset(tmp, 0, 26*4);
+        for (int j = 0; j < strs[i].length(); j++) tmp[strs[i][j] - 'a']++;
+        
+        string item = "";
+        for (int i = 0; i < 26; i++) {
+            item += (char)(tmp[i] & 0xff); 
+            item += (char)((tmp[i] >> 8) & 0xff); 
+            item += (char)((tmp[i] >> 16) & 0xff); 
+            item += (char)((tmp[i] >> 24) & 0xff);
+        }
+        
+        if (hash.find(item) == hash.end()) {
+            hash[item] = cnt++;
+            vector<string> item{strs[i]};
+            res.push_back(item);
+        } else res[ hash[item] ].push_back(strs[i]);
+    }
+    return res;
+}
+