UVALive 2775(LA 2775) Hidden Password 접미사 배열

/*
 * Author: Gatevin
 * Created Time:  2015/2/15 15:35:05
 * File Name: Mononobe_Mitsuki.cpp
 */
#include<iostream>
#include<sstream>
#include<fstream>
#include<vector>
#include<list>
#include<deque>
#include<queue>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cctype>
#include<cmath>
#include<ctime>
#include<iomanip>
using namespace std;
const double eps(1e-8);
typedef long long lint;

#define maxn 233333

/*
 * Doubling Algorithm      
 */
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 *x = wa, *y = wb, *t, i, j, p;
    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];
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;
}

char in[maxn];
int s[maxn], sa[maxn];
int n;

void solve(int N)
{
    int ans;
    for(int i = 1; i <= N; i++)
    {
        if(sa[i] < n)//             
        {
            ans = sa[i];
            while(i + 1 <= N && height[i + 1] >= n)//   lcp >= n  
            {
                i++;
                if(sa[i] < ans)//    sa[i] < n        sa[i]
                    ans = sa[i];
            }
            printf("%d
", ans);//       ,         sa[i]  
            return;
        }
    }
    return;
}

int main()
{
    int t, N;
    scanf("%d", &t);
    while(t--)
    {
        scanf("%d %s", &n, in);
        for(int i = 0; i < n; i++)
            s[i] = s[i + n] = in[i] - 'a' + 1;
        N = n << 1;
        s[N] = 0;
        da(s, sa, N + 1, 27);
        calheight(s, sa, N);
        solve(N);
    }
    return 0;
}