前缀统计 字典树模板

链接：https://ac.nowcoder.com/acm/contest/1010/A
来源：牛客网

题目描述
给定N个字符串S1,S2…SNS_1,S_2 \dots S_NS1​,S2​…SN​，接下来进行M次询问，每次询问给定一个字符串T，求S1∼SNS_1 \sim S_NS1​∼SN​中有多少个字符串是T的前缀。输入字符串的总长度不超过10610^6106，仅包含小写字母。
输入描述:

第一行两个整数N，M。接下来N行每行一个字符串Si。接下来M行每行一个字符串表示询问。

输出描述:

对于每个询问，输出一个整数表示答案

示例1
输入
复制

3 2
ab
bc
abc
abc
efg

输出
复制

2
0

模板题

#define debug
#ifdef debug
#include <time.h>
#include "/home/majiao/mb.h"
#endif

#include <iostream>
#include <algorithm>
#include <vector>
#include <string.h>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <math.h>

#define MAXN ((int)1e5+7)
#define ll long long int
#define INF (0x7f7f7f7f)
#define fori(lef, rig) for(int i=lef; i<=rig; i++)
#define forj(lef, rig) for(int j=lef; j<=rig; j++)
#define fork(lef, rig) for(int k=lef; k<=rig; k++)
#define QAQ (0)

using namespace std;

#define show(x...) \ do { \ cout << "\033[31;1m " << #x << " -> "; \ err(x); \ } while (0)

void err() { cout << "\033[39;0m" << endl; }
template<typename T, typename... A>
void err(T a, A... x) { cout << a << ' '; err(x...); }

namespace FastIO{

	char print_f[105];
	void read() {}
	void print() { putchar('\n'); }

	template <typename T, typename... T2>
		inline void read(T &x, T2 &... oth) {
			x = 0;
			char ch = getchar();
			ll f = 1;
			while (!isdigit(ch)) {
				if (ch == '-') f *= -1; 
				ch = getchar();
			}
			while (isdigit(ch)) {
				x = x * 10 + ch - 48;
				ch = getchar();
			}
			x *= f;
			read(oth...);
		}
	template <typename T, typename... T2>
		inline void print(T x, T2... oth) {
			ll p3=-1;
			if(x<0) putchar('-'), x=-x;
			do{
				print_f[++p3] = x%10 + 48;
			} while(x/=10);
			while(p3>=0) putchar(print_f[p3--]);
			putchar(' ');
			print(oth...);
		}
} // namespace FastIO
using FastIO::print;
using FastIO::read;

int n, m, Q, K;

char buf[MAXN];

#define ch (s[i]-'a')

struct Node {
	int cnt;
	Node* next[26];
	Node() : cnt(0) { memset(next, false, sizeof(next)); }
} *root = new Node();

void insert(char* s) {
	Node* now = root;
	for(int i=0; s[i]; i++) {
		if(!now->next[ch]) now->next[ch] = new Node();
		now = now->next[ch];
	}
	now->cnt ++;
}

int query(char* s) {
	Node* now = root;
	int ans = 0;
	for(int i=0; s[i]; i++) {
		if(!now->next[ch]) return ans;
		now = now->next[ch];
		ans += now->cnt;
	}
	return ans;
}

int main() {
#ifdef debug
	freopen("test", "r", stdin);
	clock_t stime = clock();
#endif
	scanf("%d %d ", &n, &m);
	for(int i=1; i<=n; i++) {
		scanf("%s ", buf);
		insert(buf);
	}
	while(m--) {
		scanf("%s ", buf);
		printf("%d\n", query(buf));
	}





#ifdef debug
	clock_t etime = clock();
	printf("rum time: %lf 秒\n",(double) (etime-stime)/CLOCKS_PER_SEC);
#endif 
	return 0;
}