KMP算法模板（C++实现）

    /*参考《算法导论》

My Code:*/

#include <iostream>
#include <cstdio>
#include <string>

using namespace std;

const int N = 1000;

string T, P;
int pi[N];

void COMPUTER_PREFIX_FUNCTION(string P){
    int m = P.length(), i, k;
    for(k = pi[0] = -1, i = 1; i < m; i++){
        while(k > -1 && P[k+1] != P[i])
            k = pi[k];
        if(P[k+1] == P[i])
            k++;
        pi[i] = k;
    }
    cout << "COMPUTER-PREFIX-FUNCTION" << endl;
    for(i = 0; i < m; i++){
        cout << pi[i] << " ";
    }
    cout << endl << endl;
}

void KMP_MATCHER(string T, string P){

    int i, n, m, k;
    n = T.length(); m = P.length();

    for(k = -1, i = 0; i < n; i++){
        while(k > -1 && P[k+1] != T[i])    k = pi[k];
        if(P[k+1] == T[i])    k++;
        if(k == m-1){
            cout << "Pattern occurs with shift " << i - m + 2 << endl;
            k = pi[k];
        }
    }
}

int main(){
    //freopen("data.in", "r", stdin);

    cin >> T >> P;
    COMPUTER_PREFIX_FUNCTION(P);
    KMP_MATCHER(T, P);
    return 0;
}