POJ 1226 后缀数组

#define _CRT_SECURE_NO_DEPRECATE
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<time.h>
#include<cmath>
#include<set>
using namespace std;
typedef long long int LL;
const int MAXN = 100 * 100 * 5;
int wa[MAXN], wb[MAXN], wv[MAXN], WS[MAXN];
int cmp(int *r, int a, int b, int l)
{
    return r[a] == r[b] && r[a + l] == r[b + l];
}
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++;
    }
    return;
}
int Rank[MAXN], height[MAXN], sa[MAXN];
void calheight(int *r, int *sa, int n){
    int i, j, k = 0;
    for (i = 1; i <= n; i++) { Rank[sa[i]] = i; }
    for (i = 0; i < n; height[Rank[i++]] = k){
        for (k ? k-- : 0, j = sa[Rank[i] - 1]; r[i + k] == r[j + k]; k++);
    }
    return;
}
int r[MAXN], len, n, t, Index[MAXN];
char str[100+5];
bool check(int x){
    set<int>se;
    for (int i = 1; i < len; i++){
        if (height[i] >= x){ //分组，把每组属于哪个原串保存在集合
            se.insert(Index[sa[i]]); se.insert(Index[sa[i - 1]]);
        }
        else{//一组的分界线，判断是否有n个串都存在集合中
            if (se.size() == n){ return true; } se.clear();
        }
    }
    if (se.size() == n){ return true; }
    return false;
}
void solve(){
    if (n == 1){ //注意特判n=1！
        printf("%d\n", strlen(str));
        return;
    }
    int L = 1, R = 100, mid, ans = 0;
    while (R >= L){
        mid = (L + R) / 2;
        if (check(mid)){
            ans = mid;
            L = mid + 1;
        }
        else{
            R = mid - 1;
        }
    }
    printf("%d\n", ans);
}
int main(){
//#ifdef kirito
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
//#endif
//    int start = clock();
    scanf("%d", &t);
    while (t--){
        scanf("%d", &n); len = 0;
        for (int i = 1, val = 0; i <= n; i++){
            scanf("%s", &str);
            for (int j = 0; j < strlen(str); j++){ //正序
                Index[len] = i; 
                r[len++] = (str[j] - ‘A‘ + 2 * n + 1);
            }
            Index[len] = i; 
            r[len++] = val++; //不同的字符隔开
            for (int j = strlen(str) - 1; j >= 0; j--){ //翻转
                Index[len] = i;
                r[len++] = (str[j] - ‘A‘ + 2 * n + 1);
            }
            Index[len] = i;
            r[len++] = val++; //不同的字符隔开
        }
        da(r, sa, len, 300);
        calheight(r, sa, len - 1);
        solve();
    }
//#ifdef LOCAL_TIME
//    cout << "[Finished in " << clock() - start << " ms]" << endl;
//#endif
    return 0;
}