UVA - 11732 "strcmp()" Anyone?左兄弟右儿子trie

input

n 2<=n<=4000

s1

s2

...

sn

1<=len(si)<=1000

output

输出用strcmp()两两比较si,sj(i!=j)要比较的次数，结果在long long范围内（相同字符比较两次，不相同字符比较一次，包括'\0'）

做法：由于字符集太大，要用左兄弟右儿子的trie保存字符，不用每次都开ch[62]个孩子

 #include <cstdio>
 #include <queue>
 #include <cstring>
 #include <iostream>
 #include <cstdlib>
 #include <algorithm>
 #include <vector>
 #include <map>
 #include <set>
 #include <ctime>
 #include <cmath>
 #include <cctype>
 #define MAX 100000
 #define LL long long
 #define mod 20071027
 struct node
 {
     int sz;
     char val;
     node*ch[];            //ch[1]兄弟，ch[0]儿子
     node()
     {
         ch[]=ch[]=NULL;
         sz=;
     }
 };
 char word[];
 int n,cas=;
 long long sum;
 long long insert(char*s,node*u)
 {
     long long sum=,lastsz=u->sz++;
     for(;*s||*(s-);s++)
     {
         if(!u->ch[])            //易错，要先把新建的结点连接到父结点才能往下走，否则新建之后父节点无法再读取到该结点
         {
             u->ch[]=new node;
             u->ch[]->val=*s;
         }
         for(u=u->ch[];u->val!=*s;u=u->ch[])
         {
             if(!u->ch[])
             {
                 u->ch[]=new node;
                 u->ch[]->val=*s;
             }
         }
         sum+=lastsz+u->sz;
         lastsz=u->sz++;
     }
     return sum;
 }
 /*//这样可以将父节点的ch和新建的结点绑定起来，传过来的是&root
 long long insert(char*s,node**u)
 {
     long long sum=0,lastsz=(*u)->sz++;
     for(;*s||*(s-1);s++)
     {
         printf("%p\n",u);
         for(u=&((*u)->ch[0]);(*u)&&(*u)->val!=*s;u=&((*u)->ch[1]));
         if(*u==NULL)
         {
             *u=new node;
             (*u)->ch[0]=(*u)->ch[1]=NULL;
             (*u)->val=*s;
         }
         sum+=lastsz+(*u)->sz;
         lastsz=(*u)->sz++;
     }
     return sum;
 }*/
 void freenode(node*u)
 {
     if(u==NULL) return;
     freenode(u->ch[]);
     freenode(u->ch[]);
     delete u;
 }
 int main()
 {
     //freopen("/home/user/桌面/in","r",stdin);
     while(scanf("%d",&n)==&&n)
     {
         sum=;
         node *root=new node;
         while(n--)
         {
             scanf("%s",word);
             sum+=insert(word,root);
         }
         printf("Case %d: %lld\n",cas++,sum);
         freenode(root);
     }
     //printf("time=%.3lf",(double)clock()/CLOCKS_PER_SEC);
     return ;
 }

 my Code

my Code

 #include <cstdio>
 #include <cstring>
 #include <iostream>
 #include <algorithm>
 using namespace std;  

 #define repf(i,a,b) for(int i=(a);i<=(b);i++)
 typedef long long ll;  

 const int N = ;
 const int MAXNODE = ;  

 int n, cas;
 ll ans;
 char str[];  

 struct STrie {
     int son[MAXNODE];
     int bro[MAXNODE];
     int val[MAXNODE];
     char ch[MAXNODE];
     int sz;  

     STrie() { sz = ; ch[] = val[] = bro[] = son[] = ; }
     void init() { sz = ; ch[] = val[] = bro[] = son[] = ; }
     // inline int idx(char c) { return c - 'a'; }  

     void insert(char *s) {
         int len = strlen(s), u = , p;
         repf (i, , len) {
             // check the brother of u
             for (p = son[u]; p; p = bro[p]) {
                 if (ch[p] == s[i])
                     break;
             }
             // cannot find out than insert
             if (!p) {
                 p = sz++;
                 ch[p] = s[i];
                 bro[p] = son[u];
                 son[p] = ;
                 val[p] = ;
                 son[u] = p;
             }
             ans += (val[u] - val[p]) * ( * i + );
             if (len == i) {
                 ans += val[p] * ( * i + );
                 val[p]++;
             }
             val[u]++;
             u = p;
         }
     }
 } trie;  

 int main() {
     // ios_base::sync_with_stdio(0);
     while (~scanf("%d", &n) && n) {
         trie.init();
         ans = ;
         repf (i, , n - ) {
             scanf("%s", str);
             trie.insert(str);
         }
         printf("Case %d: %lld\n", ++cas, ans);
     }
     return ;
 } 

copy Code