KMP算法

matrix67大神的算法讲解的太犀利了

http://www.matrix67.com/blog/archives/115

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <algorithm>
#include <cstdio>
#include <list>
#include <cstring>
using namespace std;

void kmp(char A[], char B[], int P[], int n, int m) {
    int j = -1; //表示已经匹配的位置
    for (int i = 0; i < n; i++) {
        while ((j > -1) && (B[j + 1] != A[i]))
            j = P[j];
        if (B[j + 1] == A[i])
            j = j + 1;
        if (j == m - 1) {
            cout << "Pattern occurs with shift:  " << i - m + 1 << endl;
            j = P[j];
        }
    }
}

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

int main() {
    char src[] = "rock and roll";
    char zc[] = "and";
    int p[10];

    next(p, zc, strlen(zc));
    for (int i = 0; i < strlen(zc); i++)
        cout << p[i] << "  ";
    cout << endl;
    kmp(src, zc, p, strlen(src), strlen(zc));
    return 0;
}