后缀数组

留坑待填

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

const int N = 20005;
struct SA {
    int A[N], rank[N], sa[N], n, sum[N], height[N];
    struct radix_ele {
        int id;
        int k[2];
        radix_ele(){}
        radix_ele(int a, int b, int c) { id = a, k[0] = b, k[1] = c; }
    } RE[N], RT[N];
    void radix_sort()
    {
        for (int y = 1; y >= 0; y--) {
            memset(sum, 0, sizeof sum);
            for (int i = 1; i <= n; i++) sum[RE[i].k[y]]++;
            for (int i = 1; i < N; i++) sum[i] += sum[i-1];
            for (int i = n; i >= 1; i--) RT[sum[RE[i].k[y]]--] = RE[i];
            // 注意这里要逆序，关键字相同按原顺序
            for (int i = 1; i <= n; i++) RE[i] = RT[i];
        } // 通过前缀和计算位置，进行基数排序
        for (int i = 1; i <= n; i++) {
            rank[RE[i].id] = rank[RE[i-1].id];
            if (RE[i].k[0] != RE[i-1].k[0] || RE[i].k[1] != RE[i-1].k[1])
                rank[RE[i].id]++;
        } // 计算rank，只有和前一个不同时才+1
    }
    void calc_sa()
    {
        for (int i = 1; i <= n; i++) RE[i] = radix_ele(i, A[i], 0);
        radix_sort();
        for (int k = 1; k < n; k <<= 1) {
            for (int i = 1; i <= n; i++) RE[i] = radix_ele(i, rank[i], i+k<=n?rank[i+k]:0);
            radix_sort();
        }
        for (int i = 1; i <= n; i++) sa[rank[i]] = i;
    }
    void calc_height()
    {
        int h = 0;
        for (int i = 1; i <= n; i++) {
            if (rank[i] == 1) h = 0;
            else {
                int k = sa[rank[i]-1];
                if (--h < 0) h = 0;
                while (A[i+h] == A[k+h]) h++;
            }
            height[rank[i]] = h;
        }
    }
    void init()
    {
        calc_sa();
        calc_height();
    }
} SA;
int main()
{
    scanf("%d", &SA.n);
    for (int i = 1; i <= SA.n; i++)
        scanf("%d", &SA.A[i]);
    SA.init();
    puts("--SA--");
    for (int i = 1; i <= SA.n; i++)
        cout << SA.sa[i] << ' ';
    puts("
--RANK--");
    for (int i = 1; i <= SA.n; i++)
        cout << SA.rank[i] << " ";
    puts("
--HEIGHT--");
    for (int i = 1; i <= SA.n; i++)
        cout << SA.height[i] << " ";
    return 0;
}