Create 5880_wangdongkai.cpp

From http://www.cnblogs.com/wangdongkai/p/5880122.html

HDOJ/5880_wangdongkai.cpp

@@ -0,0 +1,135 @@
+/*
+ * HDU 5880 Family View
+ * 把文本串中所有的模式串换为等长度的'*'
+ * 
+ * AC自动机
+ * 将模式串建立AC自动机，然后进行文本串匹配，求出文本串的每个前缀
+ * 所包含的最长后缀，并且是模式串，用pos数组记录位置，然后扫描一遍输出即可。
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <iostream>
+#include <algorithm>
+#include <queue>
+#include <vector>
+using namespace std;
+
+const int MAXN = 1000000+100;
+char str[MAXN];
+int pos[MAXN];
+struct Aho_Corasick
+{
+    const static int maxnode = 1000000+100;
+    const static int type = 26;
+    int next[maxnode][type],fail[maxnode],end[maxnode],l[maxnode];
+    int root,L;
+    int newnode()
+    {
+        for(int i = 0;i<type;i++)
+            next[L][i] = -1;
+        l[L]=0;
+        end[L++] = -1;
+        return L-1;
+    }
+    void init()
+    {
+        L = 0;
+        root = newnode();
+    }
+    void insert(char* str)
+    {
+        int len = strlen(str);
+        int now = root;
+        for(int i = 0;i < len;i++)
+        {
+            int id=str[i]-'a';
+            if(next[now][id] == -1)
+                next[now][id] = newnode();
+            now=next[now][id];
+        }
+        end[now]=1;
+        l[now]=len;
+    }
+    void build()
+    {
+        queue<int>Q;
+        fail[root] = root;
+        for(int i = 0;i < type;i++)
+            if(next[root][i] == -1)
+                next[root][i] = root;
+            else
+            {
+                fail[next[root][i]] = root;
+                Q.push(next[root][i]);
+            }
+        while(!Q.empty())
+        {
+            int now = Q.front();
+            Q.pop();
+            for(int i = 0;i < type;i++)
+                if(next[now][i] == -1)
+                    next[now][i] = next[fail[now]][i];
+                else
+                {
+                    fail[next[now][i]] = next[fail[now]][i];
+                    Q.push(next[now][i]);
+                }
+        }
+    }
+    void work(char* str)
+    {
+        int id;
+        int len = strlen(str);
+        int now = root;
+        memset(pos,0,sizeof(pos));
+        for(int i = 0;i < len;i++)
+        {
+            if(str[i]>='A'&&str[i]<='Z') id=str[i]-'A';
+            else if(str[i]>='a'&&str[i]<='z') id=str[i]-'a';
+            else continue;
+            now = next[now][id];
+            int temp=now;
+            while(temp != root)
+            {
+                if(end[temp] != -1)
+                {
+                    pos[i+1]-=1;
+                    pos[i-l[temp]+1]+=1;
+                    break;
+                }
+                temp = fail[temp];
+            }
+        }
+        long long cnt=0;
+        for(int i=0;i<len;i++)
+        {
+            cnt+=pos[i];
+            if(cnt<=0) printf("%c",str[i]);
+            else printf("*");
+        }
+        printf("\n");
+    }
+}AC;
+
+int main()
+{
+    int T;
+    int n;
+    scanf("%d",&T);
+    while(T--)
+    {
+        AC.init();
+        scanf("%d",&n);
+        for(int i=1;i<=n;i++)
+        {
+            scanf("%s",str);
+            AC.insert(str);
+        }
+        AC.build();
+        getchar();
+        gets(str);
+        AC.work(str);
+    }
+    return 0;
+}