テンプレート
const int N = 1000000 + 16;
struct Hash {
const unsigned long long KEY = 137;
unsigned long long h[N], p[N];
int len;
void init(const int a[], int len) {
this->len = len;
p[0] = 1;
for (int i = 1; i <= len; i++)
p[i] = p[i - 1] * KEY;
h[len] = 0;
for (int i = len - 1; i >= 0; i--)
h[i] = h[i + 1] * KEY + a[i];
}
unsigned long long get(int l, int r) {
return h[l] - h[r + 1] * p[r - l + 1];
}
unsigned long long get_for_len(int l, int len) {
return h[l] - h[l + len] * p[len];
}
};
get
メソッド\(0 \ルL \ルR&LT <LEN(A)\) 、get_for_len
メソッド([0におけるL \ \ [1、LEN(A)における(A)LEN)、LEN \ - L] \) 。
原則
\(P_I = K ^ I \)
\(H_I = \和\ limits_ {[I、\ LEN(A)中のj個の\)} a_j \ CDOT K ^ {J - I} \)
\(取得(L、R )= H_L - H_ {R + 1} \ CDOT K ^ - {R L + 1} \)
a_j \ CDOT K ^ {J \(= \和\ limits_ {[L、lenが(A))におけるj個の\} - L} -で\和\ limits_ {j個の\ [R + 1、LEN(A))} a_j \ CDOT K ^ {JR-1} \ CDOT K ^ {R-L + 1} \)
\(= \ { - L J} - a_j \ CDOT K \和\ limits_ {[R + 1、LEN(A))におけるj個の\} a_j \ CDOT K ^和\ limits_ {[L、lenが(A))におけるj個の\} ^ {JL} \)
[R + 1、LENで\(= \和\ limits_ {にj個の\ [L、R + 1)} a_j \ CDOT K ^ {JL} + \和\ limits_ {jは\ (A))} a_j \ CDOT K ^ {JL} - \和\ limits_ {j個の\で[R + 1、LEN(A))} a_j \ CDOT K ^ {JL} \)
\(= \和\ limits_ {にj個の\ [L、R + 1)} a_j \ CDOT K ^ - {J L} \)
a_j \ CDOT K ^ {J \(= \和\ limits_ {[L、R]におけるj個の\} - L} \)
ナチュラルオーバーフロー
ALL
例
#include <bits/stdc++.h>
#define DBG(x) cerr << #x << " = " << x << endl
using namespace std;
const int N = 1000000 + 16;
struct Hash {
const unsigned long long KEY = 137;
unsigned long long h[N], p[N];
int len;
void init(const int a[], int len) {
this->len = len;
p[0] = 1;
for (int i = 1; i <= len; i++)
p[i] = p[i - 1] * KEY;
h[len] = 0;
for (int i = len - 1; i >= 0; i--)
h[i] = h[i + 1] * KEY + a[i];
}
unsigned long long get(int l, int r) {
return h[l] - h[r + 1] * p[r - l + 1];
}
unsigned long long get_for_len(int l, int len) {
return h[l] - h[l + len] * p[len];
}
} hp, hs;
int a[N];
int get_ans() {
for (int i = 0; i + hs.len - 1 < hp.len; i++)
if (hs.get_for_len(0, hs.len) == hp.get_for_len(i, hs.len))
return i + 1;
return -1;
}
int main(int argc, char **argv) {
int T;
scanf("%d", &T);
while (T--) {
int n, m;
scanf("%d%d", &n, &m);
for (int i = 0; i < n; i++)
scanf("%d", &a[i]);
hp.init(a, n);
for (int i = 0; i < m; i++)
scanf("%d", &a[i]);
hs.init(a, m);
printf("%d\n", get_ans());
}
return 0;
}
/**
2
13 5
1 2 1 2 3 1 2 3 1 3 2 1 2
1 2 3 1 3
13 5
1 2 1 2 3 1 2 3 1 3 2 1 2
1 2 3 2 1
6
-1
*/