KMP算法模板(字符串匹配问题)

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int maxn = 1000005;const int maxm = 10005;struct K_M_P{    int target[maxn];    int pattern[maxm];    int next[maxm];    int target_len;    int pattren_len;};K_M_P kmp;int KMP(){    //预处理计算next数组;    kmp.next[0] = 0;    kmp.next[1] = 0;    for(int i = 1; i < kmp.pattren_len; ++i)    //递推边界初值    {        int j = kmp.next[i];        while(j && kmp.pattern[i] != kmp.pattern[j]) j = kmp.next[j];        kmp.next[i+1] = kmp.pattern[i] == kmp.pattern[j] ? j + 1 : 0;    }    //kmp    int j = 0;                                      //当前节点编号    for(int i = 0; i < kmp.target_len; ++i)         //文本串指针    {        while(j && kmp.pattern[j] != kmp.target[i]) j = kmp.next[j];    //若失配则加next[j] 向下滑行        if(kmp.pattern[j] == kmp.target[i]) j++;        if(j == kmp.pattren_len)                    //匹配成功        {            printf("%d\n", i - kmp.pattren_len + 1 + 1);    //若从零开始计数则+1+1;            return -1;        }    }    return 1;                                       //无匹配}