Number Sequence

题目

通过本题学习KMP

代码

#include<iostream>
using namespace std;

const int MAXM = 10000;
const int MAXN = 1000000;

int nextTable[MAXM];
int pattern[MAXM];
int text[MAXN];

void GetNextTable(int m){
    int j = 0;
    nextTable[j] = -1;
    int i = nextTable[j];
    while(j < m){
        if(i == -1 || pattern[j] == pattern[i]){
            i++;
            j++;
            nextTable[j] = i;
        }else{
            i = nextTable[i];
        }
    }
    return ;
}
int kmp(int n,int m){
    GetNextTable(m);
    int i = 0,j = 0;
    while (i<n && j < m){
        if(j == -1 || text[i] == pattern[j]){
            i++;
            j++;
        }else{
            j = nextTable[j];
        }
    }
    if(j == m){  //匹配成功
        return i - j + 1;
    }else{
        return -1;
    }
}
int main(){
    int caseNumber;
    scanf("%d",&caseNumber);
    while(caseNumber--){
        int n,m;
        scanf("%d%d",&n,&m);
        for(int i = 0;i < n;i++){
            scanf("%d",&text[i]);
        }
        for(int i = 0;i < m;i++){
            scanf("%d",&pattern[i]);
        }
        printf("%d
",kmp(n,m));
    }
    return 0;
}

怎么理解kmp算法中的next数组? - 江户川柯壮的回答 - 知乎 https://www.zhihu.com/question/21474082/answer/310608922