KMP字符串【KMP模板应用】

KMP字符串【KMP模板应用】

那就直接抄板子咯：

#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
int n,m;
char P[1000005];
char S[100005];
int F[1000005];
void getFail(char *P, int *f){
    int lenP = (int)strlen(P);
    f[0] = 0; f[1] = 0; //递推边界初值
    for (int i=1; i<lenP; i++) {
        int j = f[i];
        while (j&&P[i]!=P[j]) {
            j = f[j];
        }
        f[i+1] = (P[i]==P[j]?j+1:0);
    }
}
vector<int> KMP(char *T, char *P, int *f){  //主，子，存
    int lenT = strlen(T);
    int lenP = strlen(P);
    getFail(P, f);
    int j = 0; //当前结点的编号，初始为0号始点
    vector<int> ans;
    for (int i = 0; i<lenT; i++) { //文本串当前指针
        while (j && P[j]!=T[i]) //顺着失败边走，直到可以匹配
            j = f[j];
        if (P[j] == T[i])
            j++;
        if (j==lenP)
            ans.push_back(i-lenP+1);
    }
    return ans;
}
signed main(){
    IOS;
    cin>>n;
    for(int i = 0;i < n;++i)
        cin>>S[i];
    cin>>m;
    for(int i = 0;i < m;++i)
        cin>>P[i];
    vector<int> ans = KMP(P,S,F);
    for(int i = 0,j = ans.size();i < j;++i)
        cout<<ans[i]<<" ";
    return 0;
}