hdu 1251 统计难题（求前缀出现了多少次）

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1251

#include <iostream>
#include <cstring>
#include <cstdio>
#define mem(a,b) memset(a,b,sizeof(a));
using namespace std;
typedef long long ll;
const int maxn = 500005;
const ll INF = 0x3f3f3f3f;
int tot,n,trie[maxn][26],sum[maxn];
bool vis[maxn],flag;
void Insert(char *s,int rt)
{int len = strlen(s);for(int i = 0; i < len; i++){int k = s[i] -'a';if(trie[rt][k] == 0) trie[rt][k] = ++tot;sum[trie[rt][k]]++;rt = trie[rt][k];}
}
int Find(char *s,int rt)
{int len = strlen(s);for(int i = 0; i < len; i++){int k = s[i] -'a';rt = trie[rt][k];if(rt == 0) return 0;}return sum[rt];
}
int main()
{tot = 0;int rt = 0;flag = false;char s[105];while(1){gets(s);if(s[0] == NULL){break;}Insert(s,rt);}while(cin >> s) {cout << Find(s,rt) << endl;}return 0;
}