HDU1711/HDU1686 KMP

#include <bits/stdc++.h>
using namespace std;
int T,n,m;
int a[1000005],b[10005];
int nxt[10005];


void getnxt(){
    int j = 0,k = -1;
    while(j < m){
        if (k == -1 || b[j] == b[k]){
            if (b[++j] == b[++k]){
                nxt[j] = nxt[k];
            }else{
                nxt[j] = k;
            }
        }else{
            k = nxt[k];
        }
    }
}

int kmp(){
    getnxt();
    int i,j = i= 0;
    while(i < n && j < m){
        if (j == -1 || a[i] == b[j]){
            i++;
            j++;
        }else{
            j = nxt[j];
        }
    }
    if (j == m) return i-j + 1;
        else return -1;
}

int main(){
    scanf("%d",&T);
    while(T--){
        memset(nxt,-1,sizeof(nxt));
        scanf("%d%d",&n,&m);
        for (int i = 0;i < n;++i) scanf("%d",a+i);
        for (int i = 0;i < m;++i) scanf("%d",b+i);

        printf("%d
",kmp());
    }
    return 0;
}

上面是1711，下面是1686

#include <bits/stdc++.h>
using namespace std;
int nxt[10010];
char a[1000005];
char b[10010];
int n,m,T;

void getnext(){
    memset(nxt,-1,sizeof(nxt));
    int j = -1;
    nxt[0] = -1;
    int i = 0;
    while(i < m){
        while(j != -1 && b[j] != b[i]) j = nxt[j];
        i++;j++;
        nxt[i] = j;
    }
}

int kmp()
{
    int cnt = 0;
    int i,j = i = 0;
    while(i < n){
        while(j != -1 && b[j] != a[i]) j = nxt[j];
        i++;j++;
        if (j >= m){
            cnt++;
            j = nxt[j];
        }
    }
    return cnt;
}


int main()
{
    scanf("%d",&T);
    while(T--){
        scanf("%s",b);
        m = strlen(b);
        scanf("%s",a);
        n = strlen(a);
        getnext();
        printf("%d
",kmp());
    }
}