洛谷P3375 【模板】KMP字符串匹配 kmp模板

洛谷P3375 【模板】KMP字符串匹配
kmp模板

#include <bits/stdc++.h>
#define LL long long
#define GG int
#define For(i, j, k) for(register int i=j; i<=k; i++)
#define Dow(i, j, k) for(register int i=j; i>=k; i--)
using namespace std;
inline GG read() {
    GG x = 0, f = 1;
    char ch = getchar();
    while(ch<'0'||ch>'9') { if(ch=='-') f = -1; ch = getchar(); }
    while(ch>='0'&&ch<='9') { x = x*10+ch-48; ch = getchar(); }
    return x * f;
}
void write(GG x) {
    if(x<0) putchar('-'), x = -x;
    if(x>9) write(x/10);
    putchar(x%10+48);
}
inline void writeln(GG x) { write(x); putchar('
'); }

const int N = 1000011; 
int len1, len2; 
int nxt[N]; 
char s1[N], s2[N]; 

void kmp() {
    nxt[1] = 0; 
    For(i, 2, len2) {
        int x = nxt[i-1]; 
        while(x && s2[i] != s2[x+1]) 
            x = nxt[x]; 
        if(s2[i] == s2[x+1]) ++x; 
        nxt[i] = x;  
    }
    int x = 0; 
    s2[len2+1] = '#';  // 不存在的符号  
    For(i, 1, len1) {
        while(x && s1[i] != s2[x+1])  
            x = nxt[x]; 
        if(s1[i] == s2[x+1]) ++x; 
        if(x == len2) printf("%d
", i-len2+1); 
    }
}

int main() {
    scanf("%s", s1+1);  scanf("%s", s2+1); 
    len1 = strlen(s1+1); len2 = strlen(s2+1); 
    kmp();  
    For(i, 1, len2) printf("%d ", nxt[i]); 
}