[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。

View Code

#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;

}