Codeforces 1073GYet Another LCP Problem SA

Yet Another LCP Problem

把sa求出来之后， 对于每个询问用单调栈处理。

#include<bits/stdc++.h>
#define LL long long
using namespace std;

const int N = (int)2e5 + 7;
const int LOG = 18;

namespace SA {
int sa[N], rk[N], ht[N], s[N<<1], t[N<<1], p[N], cnt[N], cur[N];
#define pushS(x) sa[cur[s[x]]--] = x
#define pushL(x) sa[cur[s[x]]++] = x
#define inducedSort(v) 
    fill_n(sa, n, -1); fill_n(cnt, m, 0);                                     
    for (int i = 0; i < n; i++) cnt[s[i]]++;                                  
    for (int i = 1; i < m; i++) cnt[i] += cnt[i-1];                           
    for (int i = 0; i < m; i++) cur[i] = cnt[i]-1;                            
    for (int i = n1-1; ~i; i--) pushS(v[i]);                                  
    for (int i = 1; i < m; i++) cur[i] = cnt[i-1];                            
    for (int i = 0; i < n; i++) if (sa[i] > 0 &&  t[sa[i]-1]) pushL(sa[i]-1); 
    for (int i = 0; i < m; i++) cur[i] = cnt[i]-1;                            
    for (int i = n-1;  ~i; i--) if (sa[i] > 0 && !t[sa[i]-1]) pushS(sa[i]-1);
void sais(int n, int m, int *s, int *t, int *p) {
    int n1 = t[n-1] = 0, ch = rk[0] = -1, *s1 = s+n;
    for (int i = n-2; ~i; i--) t[i] = s[i] == s[i+1] ? t[i+1] : s[i] > s[i+1];
    for (int i = 1; i < n; i++) rk[i] = t[i-1] && !t[i] ? (p[n1] = i, n1++) : -1;
    inducedSort(p);
    for (int i = 0, x, y; i < n; i++) if (~(x = rk[sa[i]])) {
        if (ch < 1 || p[x+1] - p[x] != p[y+1] - p[y]) ch++;
        else for (int j = p[x], k = p[y]; j <= p[x+1]; j++, k++)
            if ((s[j]<<1|t[j]) != (s[k]<<1|t[k])) {ch++; break;}
        s1[y = x] = ch;
    }
    if (ch+1 < n1) sais(n1, ch+1, s1, t+n, p+n1);
    else for (int i = 0; i < n1; i++) sa[s1[i]] = i;
    for (int i = 0; i < n1; i++) s1[i] = p[sa[i]];
    inducedSort(s1);
}
template<typename T>
int mapCharToInt(int n, const T *str) {
    int m = *max_element(str, str+n);
    fill_n(rk, m+1, 0);
    for (int i = 0; i < n; i++) rk[str[i]] = 1;
    for (int i = 0; i < m; i++) rk[i+1] += rk[i];
    for (int i = 0; i < n; i++) s[i] = rk[str[i]] - 1;
    return rk[m];
}
// Ensure that str[n] is the unique lexicographically smallest character in str.
template<typename T>
void suffixArray(int n, const T *str) {
    int m = mapCharToInt(++n, str);
    sais(n, m, s, t, p);
    for (int i = 0; i < n; i++) rk[sa[i]] = i;
    for (int i = 0, h = ht[0] = 0; i < n-1; i++) {
        int j = sa[rk[i]-1];
        while (i+h < n && j+h < n && s[i+h] == s[j+h]) h++;
        if (ht[rk[i]] = h) h--;
    }
}
};
using SA::sa;
using SA::rk;
using SA::ht;

int n, q;
char s[N];
int rmq[N][LOG], Log[N];
int a[N], b[N];
int v[N], c[N];

inline int getLcp(int x, int y) {
    if(x == y) return n - sa[x];
    x++;
    int k = Log[y - x + 1];
    return min(rmq[x][k], rmq[y - (1 << k) + 1][k]);
}

int main() {
    for(int i = 2; i < N; i++) Log[i] = Log[i >> 1] + 1;
    scanf("%d%d", &n, &q);
    scanf("%s", s);
    SA::suffixArray(n, s);
    for(int i = 1; i <= n; i++) rmq[i][0] = ht[i];
    for(int j = 1; j <= Log[n]; j++) {
        for(int i = 1; i + (1 << j) - 1 <= n; i++) {
            rmq[i][j] = min(rmq[i][j - 1], rmq[i + (1 << j - 1)][j - 1]);
        }
    }
    while(q--) {
        LL ans = 0, now;
        int k, l, a_tot = 0, b_tot = 0, top;
        scanf("%d%d", &k, &l);
        for(int i = 1; i <= k; i++) {
            int x; scanf("%d", &x);
            x--;
            a[++a_tot] = rk[x];
        }
        for(int i = 1; i <= l; i++) {
            int x; scanf("%d", &x);
            x--;
            b[++b_tot] = rk[x];
        }
        sort(a + 1, a + 1 + a_tot);
        sort(b + 1, b + 1 + b_tot);
        top = now = 0;
        for(int i = 1, j = 1; i <= a_tot; i++) {
            while(j <= b_tot && b[j] <= a[i]) {
                int lcp, cnt;
                if(top) {
                    lcp = getLcp(b[j - 1], b[j]);
                    cnt = 0;
                    while(top && v[top] >= lcp) {
                        now -= 1LL * v[top] * c[top], cnt += c[top], top--;
                    }
                    if(cnt) {
                        v[++top] = lcp;
                        c[top] = cnt;
                        now += 1LL * lcp * cnt;
                    }
                }
                v[++top] = n - sa[b[j]];
                c[top] = 1;
                now += n - sa[b[j]];
                j++;
            }
            if(top) {
                int lcp = getLcp(b[j - 1], a[i]), cnt = 0;
                while(top && v[top] >= lcp) now -= 1LL * v[top] * c[top], cnt += c[top], top--;
                if(cnt) {
                    v[++top] = lcp;
                    c[top] = cnt;
                    now += 1LL * lcp * cnt;
                }
            }
            ans += now;
        }

        top =  now = 0;
        for(int i = a_tot, j = b_tot; i >= 1; i--) {
            while(j >= 1 && b[j] > a[i]) {
                int lcp, cnt;
                if(top) {
                    lcp = getLcp(b[j], b[j + 1]);
                    cnt = 0;
                    while(top && v[top] >= lcp) now -= 1LL * v[top] * c[top], cnt += c[top], top--;
                    if(cnt) {
                        v[++top] = lcp;
                        c[top] = cnt;
                        now += 1LL * lcp * cnt;
                    }
                }
                v[++top] = n - sa[b[j]];
                c[top] = 1;
                now += n - sa[b[j]];
                j--;
            }
            if(top) {
                int lcp = getLcp(a[i], b[j + 1]), cnt = 0;
                while(top && v[top] >= lcp) now -= 1LL * v[top] * c[top], cnt += c[top], top--;
                if(cnt) {
                    v[++top] = lcp;
                    c[top] = cnt;
                    now += 1LL * lcp * cnt;
                }
            }
            ans += now;
        }
        printf("%lld
", ans);
    }
    return 0;
}

/*
*/