| Time Limit: 5000MS | Memory Limit: 32768KB | 64bit IO Format: %I64d & %I64u |
Description
Given two sequences of numbers : a[1], a[2], …… , a[N], and b[1], b[2], …… , b[M] (1 <= M <= 10000, 1 <= N <= 1000000). Your task is to find a number K which make a[K] = b[1], a[K + 1] = b[2], …… , a[K + M – 1] = b[M]. If there are more than one K exist, output the smallest one.
Input
The first line of input is a number T which indicate the number of cases. Each case contains three lines. The first line is two numbers N and M (1 <= M <= 10000, 1 <= N <= 1000000). The second line contains N integers which indicate a[1], a[2], …… , a[N]. The third line contains M integers which indicate b[1], b[2], …… , b[M]. All integers are in the range of [-1000000, 1000000].
Output
For each test case, you should output one line which only contain K described above. If no such K exists, output -1 instead.
Sample Input
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
Sample Output
6 -1
Source
Hmm………..KMP模板题，char改成int就好。
AC代码：
#include <cstdio>
using namespace std;
int a[1000010], b[10010];
int n, m;
void input()
{
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]);
}
void kmp_pre(int x[], int m, int next[])
{
int i, j;
j = next[0] = -1;
i = 0;
while (i < m)
{
while (-1 != j && x[i] != x[j])
j = next[j];
next[++i] = ++j;
}
}
int next[10010];
int kmp(int x[], int m, int y[], int n)
{
int i, j;
kmp_pre(x, m, next);
i = j = 0;
while (i < n)
{
while (-1 != j && y[i] != x[j])
j = next[j];
i++, j++;
if (j == m)
return i - j + 1;
}
return -1;
}
void solve()
{
printf("%d\n", kmp(b, m, a, n));
}
int main()
{
int T;
scanf("%d", &T);
while (T--)
{
input();
solve();
}
return 0;
}
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