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hdu 5384 Danganronpa(字典树)
题意:
f(A,B) <script type="math/tex" id="MathJax-Element-1">f(A,B)</script>表示:B在A中作为子串出现的次数。
题目给出n个证据,m个子弹
Ai <script type="math/tex" id="MathJax-Element-2">A_i</script>是证据。Bi <script type="math/tex" id="MathJax-Element-3">B_i</script>是子弹。题目问:全部Bi <script type="math/tex" id="MathJax-Element-4">B_i</script>对每一个Ai <script type="math/tex" id="MathJax-Element-5">A_i</script>造成的伤害是多少,即每一个Bi <script type="math/tex" id="MathJax-Element-6">B_i</script>在Ai <script type="math/tex" id="MathJax-Element-7">A_i</script>中出现的次数总和。
解析:
不会AC自己主动机,所以就用字典树水了一发。没想到过了。
先把全部的Bi <script type="math/tex" id="MathJax-Element-24">B_i</script>插入字典树中。然后枚举每一个Ai <script type="math/tex" id="MathJax-Element-25">A_i</script>的后缀,查询后缀的每一个前缀在字典树中出现了几次。
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
typedef long long ll;
const int MAXN = (int)1e5 + 10;
const int maxnode = (int)6e5 + 10;
const int sigma_size = 26;
struct Trie {
int ch[maxnode][sigma_size];
int val[maxnode];
int sz;
void clear() { sz = 1; memset(ch[0], 0, sizeof(ch[0]));}
Trie() {clear();}
int idx(char c) { return c - ‘a‘;}
void insert(char *s, int v = 1) {
int u = 0, n = strlen(s);
for(int i = 0; i < n; i++) {
int c = idx(s[i]);
if(!ch[u][c]) {
memset(ch[sz], 0, sizeof(ch[u]));
val[sz] = 0;
ch[u][c] = sz++;
}
u = ch[u][c];
}
val[u] += v;
}
ll find(const char* s) {
int u = 0, n = strlen(s);
ll ret = 0;
for(int i = 0; i < n; i++) {
int c = idx(s[i]);
if(!ch[u][c]) return ret;
u = ch[u][c];
ret += val[u];
}
return ret;
}
} trie;
int n, m;
string A[MAXN];
char B[MAXN];
int main() {
int T;
scanf("%d", &T);
while(T--) {
scanf("%d%d", &n, &m);
trie.clear();
for(int i = 0; i < n; i++) {
cin >> A[i];
}
for(int i = 0; i < m; i++) {
scanf("%s", B);
trie.insert(B);
}
ll ans = 0;
for(int i = 0; i < n; i++) {
ans = 0;
for(int j = 0; j < A[i].size(); j++) {
ans += trie.find(A[i].c_str()+j);
}
printf("%lld\n", ans);
}
}
return 0;
}
hdu 5384 Danganronpa(字典树)