后缀数组模板

sa数组：sa[i]表示第i个后缀为suffix(sa[i])。下标从1-n，存储信息为0-(n-1)。
R数组：R[i]表示以a[i]开头的后缀在序列里面排第几。下标0-(n-1)，存储信息为1-n。
H数组：H[i]表示后缀suffix(sa[i-1])和suffix(sa[i])的最长公共前缀。下标2-n。

倍增：时间复杂度O(nlogn)，数组均开n即可。

int cmp(int *r, int a, int b, int l) {
    return (r[a] == r[b]) && (r[a+l] == r[b+l]);
}
int wa[MAXN], wb[MAXN], ws[MAXN], wv[MAXN];
int R[MAXN];//下标0->n-1 存储的是1->n之间的数
int H[MAXN];//下标2->n   H[i] >= H[i-1]-1
void DA(int *r, int *sa, int n, int m)
{
    int i, j, p, *x = wa, *y = wb, *t;
    for(i = 0; i < m; i++) ws[i] = 0;
    for(i = 0; i < n; i++) ws[x[i]=r[i]]++;
    for(i = 1; i < m; i++) ws[i] += ws[i-1];
    for(i = n-1; i >= 0; i--) sa[--ws[x[i]]] = i;
    for(j = 1, p = 1; p < n; j *= 2, m = p)
    {
        for(p = 0, i = n-j; i < n; i++) y[p++] = i;
        for(i = 0; i < n; i++) if(sa[i] >= j) y[p++] = sa[i] - j;
        for(i = 0; i < n; i++) wv[i] = x[y[i]];
        for(i = 0; i < m; i++) ws[i] = 0;
        for(i = 0; i < n; i++) ws[wv[i]]++;
        for(i = 1; i < m; i++) ws[i] += ws[i-1];
        for(i = n-1; i >= 0; i--) sa[--ws[wv[i]]] = y[i];
        for(t = x, x = y, y = t, p = 1, x[sa[0]] = 0, i = 1; i < n; i++)
            x[sa[i]] = cmp(y, sa[i-1], sa[i], j) ? p-1 : p++;
    }
}
void calh(int *r, int *sa, int n)
{
    int i, j, k = 0;
    for(i = 1; i <= n; i++) R[sa[i]] = i;
    for(i = 0; i < n; H[R[i++]] = k)
    for(k ? k-- : 0, j = sa[R[i]-1]; r[i+k] == r[j+k]; k++);
}
int sa[MAXN];//下标从1->n，存储的是0->n-1之间的数

dc3：时间复杂度O(n)，R数组和sa数组要开3倍，其他不变。H数组要开三倍，有的题目不开会RE。

#define F(x) ((x)/3+((x)%3==1?0:tb))
#define G(x) ((x)<tb?(x)*3+1:((x)-tb)*3+2)
int wa[MAXN], wb[MAXN], wv[MAXN], ws[MAXN];
int c0(int *r, int a, int b) {
    return r[a] == r[b] && r[a+1] == r[b+1] && r[a+2] == r[b+2];
}
int c12(int k, int *r, int a, int b) {
    if(k == 2) return r[a] < r[b] || r[a] == r[b] && c12(1, r, a+1, b+1);
    else return r[a] < r[b] || r[a] == r[b] && wv[a+1] < wv[b+1];
}
void Sort(int *r, int *a, int *b, int n, int m) {
    int i;
    for(i = 0; i < n; i++) wv[i] = r[a[i]];
    for(i = 0; i < m; i++) ws[i] = 0;
    for(i = 0; i < n; i++) ws[wv[i]]++;
    for(i = 1; i < m; i++) ws[i] += ws[i-1];
    for(i= n-1; i >= 0; i--) b[--ws[wv[i]]] = a[i];
}
void dc3(int *r, int *sa, int n, int m) {
    int i, j, *rn = r+n, *san = sa+n, ta = 0, tb = (n+1)/3, tbc = 0, p;
    r[n] = r[n+1] = 0;
    for(i = 0; i < n; i++) if(i % 3) wa[tbc++] = i;
    Sort(r+2, wa, wb, tbc, m);
    Sort(r+1, wb, wa, tbc, m);
    Sort(r, wa, wb, tbc, m);
    for(p = 1, rn[F(wb[0])] = 0, i = 1; i < tbc; i++)
    rn[F(wb[i])] = c0(r,wb[i-1],wb[i]) ? p-1 : p++;
    if(p < tbc) dc3(rn, san, tbc, p);
    else for(i = 0; i < tbc; i++) san[rn[i]] = i;
    for(i = 0; i < tbc; i++) if(san[i] < tb) wb[ta++] = san[i]*3;
    if(n % 3 == 1) wb[ta++] = n-1;
    Sort(r, wb, wa, ta, m);
    for(i = 0; i < tbc; i++) wv[wb[i] = G(san[i])] = i;
    for(i = 0, j = 0, p = 0; i < ta && j < tbc; p++)
    sa[p] = c12(wb[j]%3, r, wa[i], wb[j]) ? wa[i++] : wb[j++];
    for(; i < ta; p++) sa[p] = wa[i++];
    for(; j < tbc; p++) sa[p] = wb[j++];
}
int R[MAXN*3], H[MAXN*3];
void calh(int *r, int *sa, int n)
{
    int i, j, k = 0;
    for(i = 1; i <= n; i++) R[sa[i]] = i;
    for(i = 0; i < n; H[R[i++]] = k)
    for(k ? k-- : 0, j = sa[R[i]-1]; r[i+k] == r[j+k]; k++);
}
int sa[MAXN*3];