pat 1042. Shuffling Machine (20)

https://www.patest.cn/contests/pat-a-practise/1042

hash 一下顺序， 然后就是dp了。

#include <cstdio>
#include <algorithm>
using namespace std;
#define rep(i,j,k) for(int i=j;i<=k;i++)
#define inone(i) scanf("%d",&i)
const int maxn = 1e4 + 10;
int n, m, l, x, res, a[maxn], b[maxn], dp[maxn];

int main()
{
	inone(n); 
	rep(i, 1, n) a[i] = n + 1;
	inone(m);
	rep(i, 1, m) {
		inone(x);
		a[x] = i;
	}
	inone(l);
	rep (i, 1, l) inone(b[i]);
	rep(i, 1, l) rep(j, 0, i - 1)
	{
		if (a[b[i]] <= n && a[b[i]] >= a[b[j]]) dp[i] = max(dp[i], dp[j] + 1);
	}
	rep(i, 1, l)
	{
		if (a[b[i]] <= n) res = max(res, dp[i]);
	}
	printf("%d\n", res);
    return 0;
}