hdu 4641 K-string（后缀自动机 + 并查集）

来源：互联网发布：iea数据库编辑：程序博客网时间：2024/06/13 09:41
题目链接：hdu 4641 K-string
代码

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long ll;const int maxn = 300005;const int SIGMA_SIZE = 26;struct SAM {    int sz, last;    int g[maxn<<1][SIGMA_SIZE], pre[maxn<<1], step[maxn<<1];    int pos[maxn<<1], right[maxn<<1], cnt[maxn<<1];    int ridx[maxn<<1];    void newNode(int s) {        step[++sz] = s;        pre[sz] = 0;        memset(g[sz], 0, sizeof(g[sz]));    }    int idx(char ch) { return ch -'a'; }    void init() {        sz = 0, last = 1;        newNode(0);    }    void insert(char ch);    void get_tuopu();    void get_right(char* str);    int f[maxn<<1], sub[maxn<<1];    int find(int x) { return x == f[x] ? x : f[x] = find(f[x]); }    ll ans[maxn];    void solve(int m, int* op, int k);}SA;int N, M, K, op[maxn];char str[maxn];void init () {    SA.init();    scanf("%s", str);    for (int i = 0; i < N; i++)        SA.insert(str[i]);    char tmp[5];    for (int i = 1; i <= M; i++) {        scanf("%d", &op[i]);        if (op[i] == 1) {            scanf("%s", tmp);            str[N++] = tmp[0];            SA.insert(tmp[0]);        }    }    str[N] = '\0';    SA.get_tuopu();    SA.get_right(str);}int main () {    while (scanf("%d%d%d", &N, &M, &K) == 3) {        init();        SA.solve(M, op, K);    }    return 0;}void SAM::solve(int m, int* op, int k) {    ll ret = 0;    for (int i = 0; i < sz; i++) {        int u = pos[i];        if (right[u] >= k) ret += step[u] - step[pre[u]];    }    for (int i = 0; i <= sz; i++) f[i] = i, sub[i] = 0;    for (int i = m; i; i--) {        if (op[i] == 2) ans[i] = ret;        else {            int p = ridx[N--];            int fp = find(p);            while (fp && right[fp] < k) {                p = f[fp] = pre[fp];                fp = find(p);            }            if (fp == 0) continue;            sub[fp]++;            while (fp && right[fp] - sub[fp] < k) {                ret -= step[fp] - step[pre[fp]];                p = f[fp] = pre[fp];                sub[pre[fp]] += sub[fp];                fp = find(p);            }        }    }    for (int i = 1; i <= m; i++)        if (op[i] == 2) printf("%lld\n", ans[i]);}void SAM::insert(char ch) {    newNode(step[last] + 1);    int v = idx(ch), p = last, np = sz;    ridx[N] = np; //    while (p && !g[p][v]) {        g[p][v] = np;        p = pre[p];    }    if (p) {        int q = g[p][v];        if (step[q] == step[p] + 1)            pre[np] = q;        else {            newNode(step[p] + 1);            int nq = sz;            for (int j = 0; j < SIGMA_SIZE; j++) g[nq][j] = g[q][j];            pre[nq] = pre[q];            pre[np] = pre[q] = nq;            while (p && g[p][v] == q) {                g[p][v] = nq;                p = pre[p];            }        }    } else        pre[np] = 1;    last = np;}void SAM::get_tuopu() {    for (int i = 0; i <= sz; i++) cnt[i] = 0;    for (int i = 1; i <= sz; i++) cnt[step[i]]++;    for (int i = 1; i <= sz; i++) cnt[i] += cnt[i-1];    for (int i = 1; i <= sz; i++) pos[cnt[step[i]]--] = i; }void SAM::get_right(char* str) {    int p = 1, n = strlen(str);    for (int i = 0; i <= sz; i++) right[i] = 0;    for (int i = 0; i < n; i++) {        int v = idx(str[i]);        p = g[p][v];        right[p]++;    }    for (int i = sz; i; i--) {        int u = pos[i];        right[pre[u]] += right[u];    }}
0 0