diff --git a/include/cppjieba/TextRankExtractor.hpp b/include/cppjieba/TextRankExtractor.hpp
index 20d295b..8e7d18a 100644
--- a/include/cppjieba/TextRankExtractor.hpp
+++ b/include/cppjieba/TextRankExtractor.hpp
@@ -5,162 +5,162 @@
 #include "Jieba.hpp"
 
 namespace cppjieba {
-	using namespace limonp;
-	using namespace std;
+  using namespace limonp;
+  using namespace std;
 
-	class TextRankExtractor {
-	public:
-		typedef struct _Word {string word;vector<size_t> offsets;double weight;}    Word; // struct Word
-	private:
-		typedef std::unordered_map<string,Word> WordMap;
-	
-		class WordGraph{
-		private:
-			typedef double Score;
-			typedef string Node;
-			typedef std::unordered_set<Node> NodeSet;
-			typedef std::unordered_map<Node,double> Edges;
-			typedef std::unordered_map<Node,Edges> Graph;
+  class TextRankExtractor {
+  public:
+    typedef struct _Word {string word;vector<size_t> offsets;double weight;}    Word; // struct Word
+  private:
+    typedef std::unordered_map<string,Word> WordMap;
+  
+    class WordGraph{
+    private:
+      typedef double Score;
+      typedef string Node;
+      typedef std::unordered_set<Node> NodeSet;
+      typedef std::unordered_map<Node,double> Edges;
+      typedef std::unordered_map<Node,Edges> Graph;
 
-			double d;
-			Graph graph;
-			NodeSet nodeSet;
-		public:
-			WordGraph(): d(0.85) {};
-			WordGraph(double in_d): d(in_d) {};
+      double d;
+      Graph graph;
+      NodeSet nodeSet;
+    public:
+      WordGraph(): d(0.85) {};
+      WordGraph(double in_d): d(in_d) {};
 
-			void addEdge(Node start,Node end,double weight){
-				Edges temp;
-				Edges::iterator gotEdges;
-				nodeSet.insert(start);
-				nodeSet.insert(end);
-				graph[start][end]+=weight;
-				graph[end][start]+=weight;
-			}
+      void addEdge(Node start,Node end,double weight){
+        Edges temp;
+        Edges::iterator gotEdges;
+        nodeSet.insert(start);
+        nodeSet.insert(end);
+        graph[start][end]+=weight;
+        graph[end][start]+=weight;
+      }
 
-			void rank(WordMap &ws,size_t rankTime=10){
-				WordMap outSum;
-				Score wsdef, min_rank, max_rank;
+      void rank(WordMap &ws,size_t rankTime=10){
+        WordMap outSum;
+        Score wsdef, min_rank, max_rank;
 
-				if( graph.size() == 0)
-					return;
+        if( graph.size() == 0)
+          return;
 
-				wsdef = 1.0 / graph.size();
+        wsdef = 1.0 / graph.size();
 
-				for(Graph::iterator edges=graph.begin();edges!=graph.end();++edges){
-					// edges->first start节点；edge->first end节点；edge->second 权重
-					ws[edges->first].word=edges->first;
-					ws[edges->first].weight=wsdef;
-					outSum[edges->first].weight=0;
-					for(Edges::iterator edge=edges->second.begin();edge!=edges->second.end();++edge){
-						outSum[edges->first].weight+=edge->second;
-					}
-				}
-				//sort(nodeSet.begin(),nodeSet.end()); 是否需要排序?
-				for( size_t i=0; i<rankTime; i++ ){
-					for(NodeSet::iterator node = nodeSet.begin(); node != nodeSet.end(); node++ ){
-						double s = 0;
-						for( Edges::iterator edge= graph[*node].begin(); edge != graph[*node].end(); edge++ )
-							// edge->first end节点；edge->second 权重
-							s += edge->second / outSum[edge->first].weight * ws[edge->first].weight;
-						ws[*node].weight = (1 - d) + d * s;
-					}
-				}
+        for(Graph::iterator edges=graph.begin();edges!=graph.end();++edges){
+          // edges->first start节点；edge->first end节点；edge->second 权重
+          ws[edges->first].word=edges->first;
+          ws[edges->first].weight=wsdef;
+          outSum[edges->first].weight=0;
+          for(Edges::iterator edge=edges->second.begin();edge!=edges->second.end();++edge){
+            outSum[edges->first].weight+=edge->second;
+          }
+        }
+        //sort(nodeSet.begin(),nodeSet.end()); 是否需要排序?
+        for( size_t i=0; i<rankTime; i++ ){
+          for(NodeSet::iterator node = nodeSet.begin(); node != nodeSet.end(); node++ ){
+            double s = 0;
+            for( Edges::iterator edge= graph[*node].begin(); edge != graph[*node].end(); edge++ )
+              // edge->first end节点；edge->second 权重
+              s += edge->second / outSum[edge->first].weight * ws[edge->first].weight;
+            ws[*node].weight = (1 - d) + d * s;
+          }
+        }
 
-				min_rank=max_rank=ws.begin()->second.weight;
-				for(WordMap::iterator i = ws.begin(); i != ws.end(); i ++){
-					if( i->second.weight < min_rank ){
-						min_rank = i->second.weight;
-					}
-					if( i->second.weight > max_rank ){
-						max_rank = i->second.weight;
-					}
-				}
-				for(WordMap::iterator i = ws.begin(); i != ws.end(); i ++){
-					ws[i->first].weight = (i->second.weight - min_rank / 10.0) / (max_rank - min_rank / 10.0);
-				}
-			}
-		};
+        min_rank=max_rank=ws.begin()->second.weight;
+        for(WordMap::iterator i = ws.begin(); i != ws.end(); i ++){
+          if( i->second.weight < min_rank ){
+            min_rank = i->second.weight;
+          }
+          if( i->second.weight > max_rank ){
+            max_rank = i->second.weight;
+          }
+        }
+        for(WordMap::iterator i = ws.begin(); i != ws.end(); i ++){
+          ws[i->first].weight = (i->second.weight - min_rank / 10.0) / (max_rank - min_rank / 10.0);
+        }
+      }
+    };
 
-	public: 
-		TextRankExtractor(const Jieba& jieba, const string& stopWordPath) : segment_(jieba.GetDictTrie(), jieba.GetHMMModel()) {
-				LoadStopWordDict(stopWordPath);
-		}
-		~TextRankExtractor() {
-		}
+  public: 
+    TextRankExtractor(const Jieba& jieba, const string& stopWordPath) : segment_(jieba.GetDictTrie(), jieba.GetHMMModel()) {
+        LoadStopWordDict(stopWordPath);
+    }
+    ~TextRankExtractor() {
+    }
 
-		void Extract(const string& sentence, vector<Word>& keywords, size_t topN, size_t span=5,size_t rankTime=10) const {
-			vector<string> words;
-			segment_.Cut(sentence, words);
+    void Extract(const string& sentence, vector<Word>& keywords, size_t topN, size_t span=5,size_t rankTime=10) const {
+      vector<string> words;
+      segment_.Cut(sentence, words);
 
-			TextRankExtractor::WordGraph graph;
-			WordMap wordmap;
-			size_t offset = 0;
+      TextRankExtractor::WordGraph graph;
+      WordMap wordmap;
+      size_t offset = 0;
 
-			for(size_t i=0; i < words.size(); i++){
-				size_t t = offset;
-				offset += words[i].size();
-				if (IsSingleWord(words[i]) || stopWords_.find(words[i]) != stopWords_.end()) {
-					continue;
-				}
-				for(size_t j=i+1;j<i+span && j<words.size();j++){
-					if (IsSingleWord(words[j]) || stopWords_.find(words[j]) != stopWords_.end()) {
-						continue;
-					}
-					graph.addEdge(words[i],words[j],1);
-				}
-				wordmap[words[i]].offsets.push_back(t);
-			}
-			if (offset != sentence.size()) {
-				XLOG(ERROR) << "words illegal";
-				return;
-			}
+      for(size_t i=0; i < words.size(); i++){
+        size_t t = offset;
+        offset += words[i].size();
+        if (IsSingleWord(words[i]) || stopWords_.find(words[i]) != stopWords_.end()) {
+          continue;
+        }
+        for(size_t j=i+1;j<i+span && j<words.size();j++){
+          if (IsSingleWord(words[j]) || stopWords_.find(words[j]) != stopWords_.end()) {
+            continue;
+          }
+          graph.addEdge(words[i],words[j],1);
+        }
+        wordmap[words[i]].offsets.push_back(t);
+      }
+      if (offset != sentence.size()) {
+        XLOG(ERROR) << "words illegal";
+        return;
+      }
 
-			graph.rank(wordmap,rankTime);
-			
-			keywords.clear();
-			keywords.reserve(wordmap.size());
-			for (WordMap::iterator itr = wordmap.begin(); itr != wordmap.end(); ++itr) {
-				keywords.push_back(itr->second);
-			}
-			
-			topN = min(topN, keywords.size());
-			partial_sort(keywords.begin(), keywords.begin() + topN, keywords.end(), Compare);
-			keywords.resize(topN);
-		}
-	private:
-		void LoadStopWordDict(const string& filePath) {
-			ifstream ifs(filePath.c_str());
-			XCHECK(ifs.is_open()) << "open " << filePath << " failed";
-			string line ;
-			while (getline(ifs, line)) {
-				stopWords_.insert(line);
-			}
-			assert(stopWords_.size());
-		}
+      graph.rank(wordmap,rankTime);
+      
+      keywords.clear();
+      keywords.reserve(wordmap.size());
+      for (WordMap::iterator itr = wordmap.begin(); itr != wordmap.end(); ++itr) {
+        keywords.push_back(itr->second);
+      }
+      
+      topN = min(topN, keywords.size());
+      partial_sort(keywords.begin(), keywords.begin() + topN, keywords.end(), Compare);
+      keywords.resize(topN);
+    }
+  private:
+    void LoadStopWordDict(const string& filePath) {
+      ifstream ifs(filePath.c_str());
+      XCHECK(ifs.is_open()) << "open " << filePath << " failed";
+      string line ;
+      while (getline(ifs, line)) {
+        stopWords_.insert(line);
+      }
+      assert(stopWords_.size());
+    }
 
-		bool IsSingleWord(const string& str) const {
-			Unicode unicode;
-			TransCode::Decode(str, unicode);
-			if (unicode.size() == 1)
-				return true;
-			return false;
-		}
+    bool IsSingleWord(const string& str) const {
+      Unicode unicode;
+      TransCode::Decode(str, unicode);
+      if (unicode.size() == 1)
+        return true;
+      return false;
+    }
 
-		static void sortMapValue(WordMap &map,vector<Word>& result,size_t topN){
-			for(auto i=map.begin();i!=map.end();i++){
-				result.push_back(i->second);
-			}
-			partial_sort(result.begin(),result.begin()+topN,result.end(),Compare);
-		}
+    static void sortMapValue(WordMap &map,vector<Word>& result,size_t topN){
+      for(auto i=map.begin();i!=map.end();i++){
+        result.push_back(i->second);
+      }
+      partial_sort(result.begin(),result.begin()+topN,result.end(),Compare);
+    }
 
-		static bool Compare(const Word &x,const Word &y){
-			return x.weight > y.weight;
-		}
+    static bool Compare(const Word &x,const Word &y){
+      return x.weight > y.weight;
+    }
 
-		MixSegment segment_;
-		unordered_set<string> stopWords_;
-	};
+    MixSegment segment_;
+    unordered_set<string> stopWords_;
+  };
 } // namespace cppjieba
 
 #endif