[spoj][220][Relevant Phrases of Annihilation]

题目：http://www.spoj.pl/problems/PHRASES/

把right[20]开成right[N]，一直memset导致TLE；因为有字符串标记，所以字符串之间可以不用连接符；不过用连接符也可以。

还有da(arr,n+1,256)和calheight(arr,n)，注意下标。

#include <cstdio>
#include <cstring>
#include <algorithm>

#define clr(a,b) memset(a,b,sizeof(a))
using namespace std;

const int N = 100000+100;
const int inf = 0x3f3f3f3f;

int ua[N], ub[N], us[N], sa[N], arr[N], at;
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 n, int m){
    int i, j, p, *x=ua, *y=ub, *t;
    for (i=0; i<m; i++) us[i] = 0;
    for (i=0; i<n; i++) us[x[i]=r[i]]++;
    for (i=1; i<m; i++) us[i]+=us[i-1];
    for (i=n-1; i>=0; i--) sa[--us[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<m; i++) us[i]=0;
        for (i=0; i<n; i++) us[x[i]]++;
        for (i=1; i<m; i++) us[i]+=us[i-1];
        for (i=n-1; i>=0; i--) sa[--us[x[y[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++;
    }
}
int rank[N], h[N];
void calh(int *r, int n){
    int i, j, k = 0;
    for (i=1; i<=n; i++) rank[sa[i]]=i;
    for (i=0; i<n; h[rank[i++]]=k)
        for (k?k--:0,j=sa[rank[i]-1]; r[i+k]==r[j+k]; k++);
}
char str[N];

int n, left[20], right[20], f[N];

bool cal(int mid){
    for (int j=0; j<n; j++){
        if (right[j] - left[j] < mid) return false;
    }
    return true;
}

bool ok(int mid){
    int k = 0, t;
    for (int i=1; i<=at; i++){
        if (h[i] < mid){
            if (k && cal(mid)) return true;
            k = 0;
        } else {
            if (k == 0){
                clr(left, inf); clr(right, -1);
                t = f[sa[i-1]];
                left[t] = right[t] = sa[i-1];
            }
            t = f[sa[i]];
            if (sa[i] < left[t]) left[t] = sa[i];
            if (sa[i] > right[t]) right[t] = sa[i];
            k = 1;
        }
    }
    if (k && cal(mid)) return true;
    return false;
}
int main(){
    //freopen("D:/a.txt", "r", stdin);
    int T, l, mid, st, ed, ans;
    scanf("%d", &T);
    while (T--){
        ans = at = st = 0; ed = inf;
        scanf("%d", &n);
        for (int i=0; i<n; i++){
            scanf("%s", str);
            l = strlen(str), ed = min(ed, l);
            for (int j=0; j<=l; j++)
                arr[at] = (int)str[j], f[at++]=i;
        }
        da(arr, at, 256);
        calh(arr, at-1);
        while (st <= ed){
            mid = st + (ed-st)/2;
            if (ok(mid)) ans = mid, st = mid+1;
            else ed= mid - 1;
        }
        printf("%d\n", ans);
    }
    return 0;
}