Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 24393 Accepted Submission(s): 5862
题目链接:HDU 2896
题意显然就是用AC自动机了,把病毒网站的源码放在Trie图上跑一遍,如果遇到病毒id则把这个病毒放入这个网站的vector中即可且不需要回溯,但由于病毒可能之间存在子串的关系,因此要用一个数组来记录当前网站是否出现过这个病毒,不能重复出现。后台数据不强导致不记录也能AC,给一组数据:
2
aaa
aaaa
2
aaaaaa
bbaacc
答案:
web 1: 1 2
total: 1
代码:
#include <stdio.h> #include <bits/stdc++.h> using namespace std; #define INF 0x3f3f3f3f #define LC(x) (x<<1) #define RC(x) ((x<<1)+1) #define MID(x,y) ((x+y)>>1) #define CLR(arr,val) memset(arr,val,sizeof(arr)) #define FAST_IO ios::sync_with_stdio(false);cin.tie(0); typedef pair<int, int> pii; typedef long long LL; const double PI = acos(-1.0); const int maxn = 510; const int maxl = 210; const int maxweb = 1010; const int maxtar = 10010; char key[maxl], tar[maxtar]; bitset<maxn>vis; vector<int>web[maxweb]; struct Aho { struct Trie { int nxt[128]; int id, fail; inline void reset() { id = 0; fail = 0; } }; Trie L[maxn * maxl]; int sz; void init() { sz = 1; L[0].reset(); } void insert(char s[], int id) { int u = 0, len = strlen(s); for (int i = 0; i < len; ++i) { int v = s[i]; if (!L[u].nxt[v]) { L[sz].reset(); L[u].nxt[v] = sz++; } u = L[u].nxt[v]; } L[u].id = id; } void build() { L[0].fail = -1; queue<int>Q; Q.push(0); while (!Q.empty()) { int u = Q.front(); Q.pop(); for (int i = 0; i < 128; ++i) { int son = L[u].nxt[i]; if (!son) continue; Q.push(son); if (!u) L[son].fail = 0; else { int f = L[u].fail; while (~f) { if (L[f].nxt[i]) { L[son].fail = L[f].nxt[i]; break; } f = L[f].fail; } if (f == -1) L[son].fail = 0; } } } } void match(char s[], int id) { int u = 0, len = strlen(s); for (int i = 0; i < len; ++i) { int v = s[i]; if (L[u].nxt[v]) u = L[u].nxt[v]; else { int f = L[u].fail; while (~f && !L[f].nxt[v]) f = L[f].fail; if (f == -1) u = 0; else u = L[f].nxt[v]; } if (L[u].id && !vis[L[u].id]) { web[id].push_back(L[u].id); vis[L[u].id] = 1; } } } }; Aho aho; void init() { for (int i = 0; i < maxweb; ++i) web[i].clear(); aho.init(); } int main(void) { int n, m, i, j; while (~scanf("%d", &n)) { init(); for (i = 1; i <= n; ++i) { scanf("%s", key); aho.insert(key, i); } aho.build(); scanf("%d", &m); for (i = 1; i <= m; ++i) { scanf("%s", tar); vis.reset(); aho.match(tar, i); } int tot = 0; for (i = 1; i <= m; ++i) { int sz = web[i].size(); if (!sz) continue; ++tot; sort(web[i].begin(), web[i].end()); printf("web %d: ", i); for (j = 0; j < sz; ++j) printf("%d%s", web[i][j], j == sz - 1 ? "\n" : " "); } printf("total: %d\n", tot); } return 0; }
原文:http://www.cnblogs.com/Blackops/p/6424894.html