题意:
有n个字符串和一个文本串T,求那些字符串在文本中出现的次数最多,并按输入顺序输出。
AC自动机,板子题
#include<map> #include<cstdio> #include<cstring> #include<iostream> #include<algorithm> #include<vector> #include<queue> using namespace std; const int SIGMA_SIZE = 26; const int MAXNODE = 11000; const int MAXS = 150 + 10; map<string, int> ms; struct AhoCorasickAutomata { int ch[MAXNODE][SIGMA_SIZE]; int f[MAXNODE]; int val[MAXNODE]; int last[MAXNODE]; int cnt[MAXS]; int sz; void init() { sz = 1; memset(ch[0], 0, sizeof ch[0] ); memset(cnt, 0, sizeof cnt ); ms.clear(); } int idx(char c) { return c - 'a'; } void insert(char *s, int v) { 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[sz] ); val[sz] = 0; ch[u][c] = sz++; } u = ch[u][c]; } val[u] = v; ms[string(s)] = v; } void print(int j) { if(j) { cnt[val[j]]++; print(last[j]); } } int find(char* T) { int n = strlen(T); int j = 0; for(int i=0; i<n; ++i) { int c = idx(T[i]); while(j && !ch[j][c]) j = f[j]; j = ch[j][c]; if(val[j]) print(j); else if(last[j]) print(last[j]); } } void getFail() { queue<int> q; f[0] = 0; for(int c = 0; c <SIGMA_SIZE; ++c) { int u = ch[0][c]; if(u) { f[u] = 0; q.push(u); last[u] = 0; } } while(!q.empty()) { int r = q.front(); q.pop(); for(int c =0; c<SIGMA_SIZE; ++c) { int u = ch[r][c]; if(!u) continue; q.push(u); int v = f[r]; while(v && !ch[v][c]) v = f[v]; f[u] = ch[v][c]; last[u] = val[f[u]]?f[u]:last[f[u]]; } } } }; AhoCorasickAutomata ac; char text[1000001], p[160][80]; int n; int main() { while(~scanf("%d", &n)&&n) { ac.init(); for(int i=1; i<=n; ++i) { scanf("%s", p[i]); ac.insert(p[i], i); } ac.getFail(); scanf("%s", text); ac.find(text); int best = 0; for(int i=1; i<=n; ++i) if(ac.cnt[i]>best) best = ac.cnt[i]; printf("%d\n", best); for(int i=1; i<=n; ++i) if(ac.cnt[ms[string(p[i])]]==best) printf("%s\n", p[i]); } return 0; }