[学习笔记] 后缀数组

参考：https://www.cnblogs.com/zwfymqz/p/8413523.html

代码：

/*
* @Author: chenkexing
* @Date:   2020-01-19 19:14:09
* @Last Modified by:   chenkexing
* @Last Modified time: 2020-01-31 22:12:27
*/
// #pragma GCC optimize(2)
// #pragma GCC optimize(3)
// #pragma GCC optimize(4)
#include <algorithm>
#include <iterator>
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <iomanip>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <list>
#include <map>
#include <set>
#include <cassert>
// #include<bits/extc++.h>
// using namespace __gnu_pbds;
using namespace std;
#define pb push_back
#define fi first
#define se second
#define debug(x) cerr << #x << " := " << x << endl;
#define bug cerr << "-----------------------" << endl;
#define FOR(a, b, c) for (int a = b; a <= c; ++a)

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int inf = 0x3f3f3f3f;
const ll inff = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
template <typename T>
inline T read(T &x) {
    x = 0;
    int f = 0;
    char ch = getchar();
    while (ch < '0' || ch > '9') f |= (ch == '-'), ch = getchar();
    while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
    return x = f ? -x : x;
}

/**********showtime************/

const int maxn = 1e6 + 9;
char str[maxn];

int sa[maxn], rk[maxn], tp[maxn * 2];
int box[maxn];
int n;

// 桶排序
void tsort(int m) {
    for (int i = 0; i <= m; i++) box[i] = 0;
    for (int i = 1; i <= n; i++) box[rk[i]]++;
    for (int i = 1; i <= m; i++)
        box[i] += box[i - 1];
    for (int i = n; i >= 1; i--) {
        sa[box[rk[tp[i]]]--] = tp[i];
    }
}

int height[maxn];
// height[i] 表示(排名为i的后缀)和(排名为i-1的后缀)的lcp
void getH() {
    int j, k = 0;
    for (int i = 1; i <= n; i++) {
        if (k) k--;
        j = sa[rk[i] - 1];
        while (str[i + k] == str[j + k]) k++;
        height[rk[i]] = k;
    }
}

int main() {
    scanf("%s", str + 1);
    n = strlen(str + 1);

    for (int i = 1; i <= n; i++) {
        rk[i] = str[i] - '0';
        tp[i] = i;
    }

    tsort(200);

    for (int w = 1, p = 0, m = 200; p < n; w = w * 2, m = p) {
        p = 0;
        for (int i = 1; i <= w; i++) tp[++p] = n - i + 1;
        for (int i = 1; i <= n; i++) {
            if (sa[i] > w) tp[++p] = sa[i] - w;
        }
        // debug(p);
        tsort(m);

        for (int i = 1; i <= n; i++) tp[i] = rk[i];

        rk[sa[1]] = p = 1;
        for (int i = 2; i <= n; i++) {
            if (tp[sa[i]] == tp[sa[i - 1]] && tp[sa[i] + w] == tp[sa[i - 1] + w])
                rk[sa[i]] = p;
            else
                rk[sa[i]] = ++p;
        }
    }
    for (int i = 1; i <= n; i++) printf("%d ", sa[i]);
    puts("");
    return 0;
}