字符串匹配算法比较

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define MAX_TEXT_LEN 1000005
#define MAX_PATTERN_LEN 100005

char text[MAX_TEXT_LEN];
char pattern[MAX_PATTERN_LEN];
int next[MAX_PATTERN_LEN];

void buildNext(char *p, int m) {
    int j = 0;
    next[0] = 0;
    for (int i = 1; i < m; i++) {
        while (j > 0 && p[i] != p[j]) {
            j = next[j - 1];
        }
        if (p[i] == p[j]) {
            j++;
        }
        next[i] = j;
    }
}

char* kmpSearch(char *t, int n, char *p, int m) {
    if (m == 0) return NULL;
    
    buildNext(p, m);

    int j = 0;
    for (int i = 0; i < n; i++) {

        while (j > 0 && t[i] != p[j]) {
            j = next[j - 1];
        }

        if (t[i] == p[j]) {
            j++;
        }

        if (j == m) {
            return &t[i - m + 1];
        }
    }
    return NULL;
}

int main() {
    if (scanf("%s", text) != 1) return 0;
    int n_len = strlen(text);

    int n;
    if (scanf("%d", &n) != 1) return 0;

    while (n--) {
        scanf("%s", pattern);
        int m_len = strlen(pattern);

        if (m_len > n_len) {
            printf("Not Found\n");
            continue;
        }

        char *result = kmpSearch(text, n_len, pattern, m_len);

        if (result != NULL) {

            printf("%s\n", result);
        } else {
            printf("Not Found\n");
        }
    }

    return 0;
}