|poj 1226|后缀数组|二分|Substrings

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poj 1226
几本上与这题一样，只不过这里还要把读入的字符串的翻转后的字符串也要连上
#include<cstdio>#include<cstring>#include<algorithm>#include<vector>#define ms(i, j) memset(i, j, sizeof i)#define FN2 "poj1226" using namespace std;const int MAXN = 100 + 10;char s[MAXN];int mini, t, n, m, a[2*MAXN*MAXN], belong[2*MAXN*MAXN], SA[2*MAXN*MAXN], rk[2*MAXN*MAXN], tp[2*MAXN*MAXN], tax[2*MAXN*MAXN], height[2*MAXN*MAXN];bool cmp(int *f, int i, int k) {return f[SA[i]]==f[SA[i-1]]&&f[SA[i]+k]==f[SA[i-1]+k];}void build() {    for (int i=0;i<m;i++) tax[i] = 0;    for (int i=0;i<n;i++) tax[rk[i]=a[i]]++;    for (int i=1;i<m;i++) tax[i] += tax[i-1];    for (int i=n-1;i>=0;i--) SA[--tax[rk[i]]] = i;    int p;    for (int k=1;k<=n;k*=2) {        p = 0;        for (int i=n-k;i<n;i++) tp[p++] = i;        for (int i=0;i<n;i++) if (SA[i]>=k) tp[p++] = SA[i] - k;        for (int i=0;i<m;i++) tax[i] = 0;        for (int i=0;i<n;i++) tax[rk[tp[i]]]++;        for (int i=1;i<m;i++) tax[i] += tax[i-1];        for (int i=n-1;i>=0;i--) SA[--tax[rk[tp[i]]]] = tp[i];          swap(rk, tp), p = 0, rk[SA[0]] = 0;        for (int i=1;i<n;i++) rk[SA[i]] = cmp(tp, i, k) ? p : ++p;        if (++p>=n) break;        m = p;    }}void getH() {    int k = 0;    for (int i=0;i<n;i++) {        if (k) k--;        int j = SA[rk[i]-1];        while (a[i+k]==a[j+k]) k++;        height[rk[i]] = k;    }}void init() {    n = 0, m = 200, mini = 200000000;    scanf("%d", &t);    for (int i=0;i<t;i++) {        scanf("%s", s);        int l1 = strlen(s);        mini = min(l1, mini);        for (int j=0;j<l1;j++) {            belong[n] = i;            a[n++] = s[j];         }        a[n++] = m++;        for (int j=l1-1;j>=0;j--) {            belong[n] = i;            a[n++] = s[j];         }        a[n++] = m++;    }    a[n-1] = 0;    m += 5; }int used[MAXN];bool check(int x) {    int tot = 0;    ms(used, 0);    for (int i=2;i<n;i++) {        if (height[i]<x) {            ms(used, 0);            tot = 0;            continue;        }        if (!used[belong[SA[i-1]]]) used[belong[SA[i-1]]] = true, ++tot;        if (!used[belong[SA[i]]]) used[belong[SA[i]]] = true, ++tot;        if (tot>=t) return true;    }    return false;}void solve() {    build(), getH();    int l = 1, r = mini + 1, ans = 0;    while (l<r) {        int mid = (l+r)/2;        if (check(mid)) {            ans = mid;            l = mid + 1;        } else r = mid;    }    printf("%d\n", ans);}int main() {    #ifndef ONLINE_JUDGE    freopen(FN2".in","r",stdin);freopen("1.out","w",stdout);    #endif    int kase; scanf("%d", &kase);    while(kase--) init(), solve();    return 0;}
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