UVA 11107-life Forms (suffix array)

Topic Link: UVA 11107-life Forms

Title: Given n strings, the longest string is a substring of N/2 string.

Problem-solving ideas: suffix array, after processing the suffix array, the binary length, each traversal of the height array, when the length is insufficient to segment, if there is a section containing N/2 starting point, then the feasible length.

#include <cstdio> #include <cstring> #include <set> #include <algorithm> using namespace std;

const int maxlen = 200005;
    struct Suffix_arr {int n, S[maxlen];
    int Tmp_one[maxlen], Tmp_two[maxlen], C[maxlen];

    int Sa[maxlen], Rank[maxlen], Height[maxlen];
    void Init ();
    void Build_arr (int m);
void Get_height ();

}suf;

int N, MaxLen, Id[maxlen];
    void Init () {maxlen = 0;
    Suf.init ();

    Char word[1005];

        for (int i = 0; i < N; i++) {scanf ("%s", word);
            if (N = = 1) {printf ("%s\n", word);
        Return
        } int len = strlen (word);

        MaxLen = Max (MaxLen, Len);
            for (int j = 0; J < Len; J + +) {ID[SUF.N] = i;
        suf.s[suf.n++] = Word[j];
    } suf.s[suf.n++] = ' Z ' + i + 1;
    } suf.build_arr (' Z ' + N + 1);
Suf.get_height ();

    } bool Judge (int l, int flag) {set<int> vis;
    Vis.insert (Id[suf.sa[0]); For (int i = 1; i < SUF.N;

        i++) {while (I < SUF.N && Suf.height[i] >= l) Vis.insert (id[suf.sa[i++]]);

            if (Vis.size () * 2 > N) {if (flag) return true;
            for (int j = 0; J < L; j + +) printf ("%c", Suf.s[suf.sa[i-1] + j]);
        printf ("\ n");
        } vis.clear ();
    Vis.insert (Id[suf.sa[i]);
} return false;

    } void Solve () {if (N = = 1) return;
        if (!judge (1, 1)) {printf ("? \ n");
    Return
    } int L = 1, r = maxlen + 1;
        while (L < r) {int mid = (L + r)/2;
        if (Judge (Mid, 1)) L = mid + 1;
    else R = Mid;
} judge (L-1, 0);
    } int main () {int cas = 0;

        while (scanf ("%d", &n) = = 1 && N) {if (cas++) printf ("\ n");
        Init ();
    Solve ();
} return 0;

} void Suffix_arr::init () {n = 0;} void Suffix_arR::get_height () {for (int i = 0; i < n; i++) rank[sa[i]] = i;
    int k = 0;

        for (int i = 0; i < n; i++) {if (k) k--;

        if (rank[i] = = 0) continue;
        Int j = Sa[rank[i]-1];
        while (s[i+k] = = S[j+k]) k++;
    Height[rank[i]] = k;

    }} void Suffix_arr::build_arr (int m) {int *x = Tmp_one, *y = Tmp_two;
    for (int i = 0; i < m; i++) c[i] = 0;
    for (int i = 0; i < n; i++) c[x[i] = s[i]]++;
    for (int i = 1; i < m; i++) c[i] + = c[i-1];

    for (int i = n-1; I >= 0; i--) sa[--c[x[i]] = i;
        for (int k = 1; k <= N; k <<= 1) {int mv = 0;
        for (int i = n-k; i < n; i++) y[mv++] = i;
        for (int i = 0; i < n; i++) if (Sa[i] >= k) {y[mv++] = sa[i]-K;
        } for (int i = 0; i < m; i++) c[i] = 0;
        for (int i = 0; i < n; i++) c[x[y[i]]]++;
        for (int i = 1; i < m; i++) c[i] + = c[i-1]; for (int i = n-1;; = 0;

        i--) sa[--c[x[y[i]] [y[i];
        Swap (x, y); MV = 1;
        X[sa[0]] = 0; for (int i = 1; i < n; i++) x[sa[i]] = (y[sa[i-1] [= Y[sa[i]] && y[sa[i-1] + K] = = Y[sa[i] + K]?

        Mv-1: mv++);
        if (MV >= N) break;
    m = mv; }
}