hdu, KMP algorithm, linear string search algorithm, a nice reference provided

reference:
Rabin-Karp and Knuth-Morris-Pratt Algorithms By TheLlama– TopCoder Member https://www.topcoder.com/community/data-science/data-science-tutorials/introduction-to-string-searching-algorithms/
// to be improved

#include <cstdio>#include <cstring>#include <algorithm>#define MAXN 1000005#define MAXM 10005int nums[MAXN];int cnums[MAXM];int ffunc[MAXM]={0};int main() {#ifndef ONLINE_JUDGE    freopen("in.txt","r",stdin);#endif    int T,n,m,i,j,k, res;    int *p,*pend, *q, *r, *rend;    if(scanf("%d",&T)!=1) return -1;    while(T-->0 && scanf("%d%d",&n,&m)==2 && n>=m && m>0) {        for(i=1;i<=n;++i) scanf("%d",&nums[i]);        for(i=1;i<=m;++i) scanf("%d",&cnums[i]);        for(i=2;i<=m;++i) {            for(j=ffunc[i-1];;j=ffunc[j]) {                if(cnums[j+1]==cnums[i] || j==0 && --j) break;            }            ffunc[i]=j+1;        }        for(i=1, k=0;;) {            if(nums[i]==cnums[k+1]) { ++k; }            else if(k>0) { k=ffunc[k]; continue; }            if(++i>n || k>=m) break;        }        res=k!=m?-1:i-m;        printf("%d\n",res);    }    return 0;}