【Trie】 UVA1401 Remember the Word - 教程

代码

#include <string.h>
  #include <stdlib.h>
    #include <algorithm>
      #include <vector>
        #include <functional>
          #include <math.h>
            #include <string>
              #include <iostream>
                using namespace std;
                typedef long long ll;
                typedef pair<int, int> pii;
                  #define _for(i, a, b) for (int i = (a); i < (b); i++)
                  #define _rep(i, a, b) for (int i = (a); i <= (b); i++)
                  #define fio ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
                  #define reg register
                  #define ri reg int
                  namespace faio
                  {
                  char buf[1 << 20], *p1, *p2;
                  #define getchar() (p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1 << 20, stdin), p1 == p2) ? EOF: *p1++)
                  template <typename T> inline void read(T &t) {
                    ri v = getchar();T f = 1;t = 0;
                    while (!isdigit(v)) {if (v == '-')f = -1;v = getchar();}
                    while (isdigit(v)) {t = (t << 3) + (t << 1) + v - '0';v = getchar();}
                    t *= f;
                    }
                    template <typename T,typename... Args> inline void read(T &t, Args&... args) {read(t);read(args...);}
                      }
                      constexpr int N = 300010, mod = 20071027;
                      char str[N], word[128];
                      int dp[N];
                      typedef struct Trie_t
                      {
                      bool is_end;
                      Trie_t* son[26];
                      }*Trie;
                      Trie NewNode() {
                      Trie ret = (Trie) malloc(sizeof(Trie_t));
                      for (int i = 0; i < 26; i++) ret->son[i] = NULL;
                        ret->is_end = false;
                        return ret;
                        }
                        void FreeNode(Trie p) { // 释放 Trie 树
                        if (p == NULL) return ;
                        for (int i = 0; i < 26; i++) FreeNode(p->son[i]);
                          free(p);
                          }
                          void insert(Trie root, const char* _str)
                          {
                          Trie u = root; int len = strlen(_str);
                          for (int i = 0; i < len; i++) {
                          int idx = _str[i] - 'a';
                          if (u == NULL) printf("u is NULL");
                          if (u->son[idx] == NULL) u->son[idx] = NewNode();
                          u = u->son[idx];
                          }
                          u->is_end = true;
                          }
                          void solve(Trie root)
                          {
                          static int Kase = 0;
                          int n = strlen(str); dp[n] = 1;
                          for (int i = n - 1; i >= 0; i--) {
                          // 在 Trie 树里面找
                          Trie u = root;
                          for (int j = i; j < n; j++) {
                          int idx = str[j] - 'a';
                          if (u->son[idx] == NULL) break;
                          u = u->son[idx];
                          if (u->is_end) dp[i] = (dp[i] + dp[j + 1] + mod) % mod;
                          }
                          }
                          printf("Case %d: %d\n", ++Kase, dp[0]);
                          }
                          int main()
                          {
                          while (scanf("%s", str) == 1) {
                          int p; scanf("%d", &p);
                          Trie root = NewNode();
                          memset(dp, 0, sizeof(dp));
                          while (p--) {
                          scanf("%s", word);
                          insert(root, word);
                          }
                          solve(root);
                          FreeNode(root);
                          }
                          return 0;
                          }