KMP算法

http://jakeboxer.com/blog/2009/12/13/the-knuth-morris-pratt-algorithm-in-my-own-words/

1.partial_match_table的建立
2.查找

#include <iostream>
#include <string>
#include <vector>
#include <assert.h>

using namespace std;

void partial_match_table(string& input, vector<int>& partial_mt)
{
    assert(input.size() != 0);
    for (int i = 0; i < input.size(); i++) {
        int com = 0;
        for (int j = 1; j <= i; j++) {
            string prefix = input.substr(0, j);
            string postfix = input.substr(i - j + 1, j);
            if (!prefix.compare(postfix)) {
                com = j;
            }
        }
        partial_mt.push_back(com);
    }
}

void KMP(string& test, string& match, vector<int>& partial_mt)
{
    int i = 0;
    int j = 0;
    while (i < test.size()) {
        while (j < match.size()) {
            if (test.at(i) == match.at(j)) {
                i++;
                j++;
            }
            else if (j == 0){
                i ++;
            }
            else {
                i += (j - partial_mt.at(j-1));
                j = 0;
            }
        }
        cout << i-j+1 << endl;
        break;
    }
}

int main()
{
    vector<int> res;
    string test = "ABCDABD";
    string match = "BBC ABCDAB ABCDABCDABDE";
    partial_match_table(test, res);
    KMP(match, test, res);
    system("pause");
    return 0;
}
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