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Java code to implement the Z algorithm

Wandering Warbler answered on February 7, 2023 Popularity 1/10 Helpfulness 1/10

answer Java code to implement the Z algorithm

Java code to implement the Z algorithm

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import java.util.*;

public class Main {
    static int MOD = 1000000007;
    static int n, k, cnt, ans;
    static char[] s, t;
    static int[] z, f;
    static Set<String> set = new HashSet<>();

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        s = sc.nextLine().toCharArray();
        n = s.length;
        k = sc.nextInt();
        while (k-- > 0) {
            t = sc.next().toCharArray();
            int len = t.length;
            set.add(new String(t));
            z = new int[len];
            getZ(t);
            int j = 0;
            for (int i = 1; i < len; i++) {
                if (i + z[i] == len) {
                    j = i;
                    break;
                }
            }
            f = new int[len];
            for (int i = j; i < len; i++)
                f[i - j] = i;
            for (int i = 0; i < j; i++)
                f[i + len - j] = i;
            int cur = 0;
            for (int i = 0; i < n; i++) {
                if (cur + len > n)
                    break;
                boolean flag = true;
                for (int p = f[i - cur]; p < len && flag; p++) {
                    if (s[i] != t[p])
                        flag = false;
                    i++;
                }
                if (flag) {
                    cur += len;
                    i--;
                }
            }
            if (cur == n)
                ans++;
        }
        System.out.println(ans % MOD);
    }

    static void getZ(char[] str) {
        int len = str.length;
        int l = 0, r = 0;
        for (int i = 1; i < len; i++) {
            if (i > r) {
                l = r = i;
                while (r < len && str[r - l] == str[r])
                    r++;
                z[i] = r - l;
                r--;
            } else {
                int k = i - l;
                if (z[k] < r - i + 1)
                    z[i] = z[k];
                else {
                    l = i;
                    while (r < len && str[r - l] == str[r])
                        r++;
                    z[i] = r - l;
                    r--;
                }
            }
        }
    }
}

Popularity 1/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: algorithm java

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Contributed on Feb 07 2023

Wandering Warbler

0 Answers Avg Quality 2/10

Java code to implement the Z algorithm

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