• 【bzoj3277&&3474】串



    *题目描述:
    字符串是oi界常考的问题。现在给定你n个字符串,询问每个字符串有多少子串(不包括空串)是所有n个字符串中至少k个字符串的子串(注意包括本身)。


    *输入:
    第一行两个整数n,k。接下来n行每行一个字符串。


    *输出:
    输出一行n个整数,第i个整数表示第i个字符串的答案。


    *样例输入:
    3 1
    abc
    a
    ab


    *样例输出:
    6 1 3


    *提示:
    对于100%的数据,n,k,l<=100000


    *来源:
    后缀数组


    *题解:
    广义后缀自动机。建完广义后缀自动机后,统计一下某个节点在所有字符串中出现的次数,对于次数大于等于k的节点统计一下答案。


    *代码:

    #include <cstdio>
    #include <cstring>
    #include <algorithm>
    #include <cmath>
    
    #ifdef WIN32
        #define LL "%I64d"
    #else
        #define LL "%lld"
    #endif
    
    #ifdef CT
        #define debug(...) printf(__VA_ARGS__)
        #define setfile() 
    #else
        #define debug(...)
        #define filename ""
        #define setfile() freopen(filename".in", "r", stdin); freopen(filename".out", "w", stdout);
    #endif
    
    #define R register
    #define getc() (S == T && (T = (S = B) + fread(B, 1, 1 << 15, stdin), S == T) ? EOF : *S++)
    #define dmax(_a, _b) ((_a) > (_b) ? (_a) : (_b))
    #define dmin(_a, _b) ((_a) < (_b) ? (_a) : (_b))
    #define cmax(_a, _b) (_a < (_b) ? _a = (_b) : 0)
    #define cmin(_a, _b) (_a > (_b) ? _a = (_b) : 0)
    char B[1 << 15], *S = B, *T = B;
    inline int FastIn()
    {
        R char ch; R int cnt = 0; R bool minus = 0;
        while (ch = getc(), (ch < '0' || ch > '9') && ch != '-') ;
        ch == '-' ? minus = 1 : cnt = ch - '0';
        while (ch = getc(), ch >= '0' && ch <= '9') cnt = cnt * 10 + ch - '0';
        return minus ? -cnt : cnt;
    }
    #define maxn 100010
    struct sam
    {
        sam *next[26], *fa;
        int val, last_vis, c;
        bool vis;
        long long sum;
    }mem[maxn << 1], *tot = mem;
    inline sam *extend(R sam *p, R int c)
    {
        if (p -> next[c])
        {
            R sam *q = p -> next[c];
            if (q -> val == p -> val + 1)
                return q;
            else
            {
                R sam *nq = ++tot;
                memcpy(nq -> next, q -> next, sizeof nq -> next);
                nq -> val = p -> val + 1;
                nq -> fa = q -> fa;
                q -> fa = nq;
                for ( ; p && p -> next[c] == q; p = p -> fa)
                    p -> next[c] = nq;
                return nq;
            }
        }
        R sam *np = ++tot;
        np -> val = p -> val + 1;
        for ( ; p && !p -> next[c]; p = p -> fa) p -> next[c] = np;
        if (!p)
            np -> fa = mem;
        else
        {
            R sam *q = p -> next[c];
            if (q -> val == p -> val + 1)
                np -> fa = q;
            else
            {
                R sam *nq = ++tot;
                memcpy(nq -> next, q -> next, sizeof nq -> next);
                nq -> val = p -> val + 1;
                nq -> fa = q -> fa;
                q -> fa = np -> fa = nq;
                for ( ; p && p -> next[c] == q; p = p -> fa)
                    p -> next[c] = nq;
            }
        }
        return np;
    }
    void get_ans(R sam *x)
    {
        if (x == mem || x -> vis) return;
        x -> vis = 1; get_ans(x -> fa); x -> sum += x -> fa -> sum;
    }
    char str[maxn], tot_str[maxn];
    int left[maxn], right[maxn];
    int main()
    {
    //  setfile();
        R int n, k;
        scanf("%d%d", &n, &k);
        R int tot_len = 0;
        for (R int i = 1; i <= n; ++i)
        {
            scanf("%s", str);
            R sam* x = mem;
            R int len = strlen(str);
            left[i] = tot_len;
            right[i] = tot_len = len + tot_len - 1; ++tot_len;
            memcpy(tot_str + left[i], str, len * sizeof(char));
            for (R int j = 0; j < len; ++j)
                x = extend(x, str[j] - 'a');
        }
        for (R int i = 1; i <= n; ++i)
        {
            R sam *x = mem, *t;
            for (R int j = left[i]; j <= right[i]; ++j)
            {
                x = x -> next[tot_str[j] - 'a'];
                for (t = x; t && t -> last_vis != i; t = t -> fa)
                    t -> last_vis = i, t -> c++;
            }
        }
        for (R sam *iter = mem + 1; iter <= tot; ++iter)
            iter -> sum = iter -> c >= k ? iter -> val - iter -> fa -> val : 0;
        for (R sam *iter = mem + 1; iter <= tot; ++iter)
            get_ans(iter);
        for (R int i = 1; i <= n; ++i)
        {
            R sam *x = mem; R long long ans = 0;
            for (R int j = left[i]; j <= right[i]; ++j)
                x = x -> next[tot_str[j] - 'a'], ans += x -> sum;
            printf("%lld ", ans );
        }
        return 0;
    }
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  • 原文地址:https://www.cnblogs.com/cocottt/p/6764992.html
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