spoj 8222 Substrings（后缀自动机）

来源：互联网发布：linux 查看代理服务器编辑：程序博客网时间：2024/05/21 23:17
题目链接：spoj 8222 Substrings
代码

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long ll;const int maxn = 250005;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];    void newNode(int s) {        step[++sz] = s;        pre[sz] = 0;        memset(g[sz], 0, sizeof(g[sz]));    }    int idx(char ch) {         if (ch >= 'A' && ch <= 'Z') return ch - 'A' + 26;        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];    void solve (int n) {        memset(f, 0, sizeof(f));        for (int i = 1; i <= sz; i++) {            int u = step[i];            f[u] = max(f[u], right[i]);        }        for (int i = n-1; i; i--)            f[i] = max(f[i], f[i+1]);        for (int i = 1; i <= n; i++)            printf("%d\n", f[i]);    }}SA;int K;char s[maxn];int main () {    scanf("%s", s);    SA.init();    int n = strlen(s);    for (int i = 0; i < n; i++)        SA.insert(s[i]);    SA.get_tuopu();    SA.get_right(s);    SA.solve(n);    return 0;}void SAM::insert(char ch) {    newNode(step[last] + 1);    int v = idx(ch), p = last, np = sz;    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];    }}
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