P1541 [NOIP2010 提高组] 乌龟棋(线性dp)

P1541 [NOIP2010 提高组] 乌龟棋https://www.luogu.com.cn/problem/P1541

#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <cstring>
#include <set>
#include <cmath>
#include <map>
#include <cstdlib>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
const int MN = 65005;
const int MAXN = 2000010;
const int INF = 0x3f3f3f3f;
#define IOS ios::sync_with_stdio(false)

int n, m;
int a[MAXN];
int b[12];
int dp[45][45][45][45];
int main() {
	scanf("%d %d", &n, &m);
	for (int i = 1; i <= n; i++) {
		scanf("%d", a + i);
	}
	int x;
	for (int i = 1; i <= m; i++) {
		scanf("%d", &x);
		b[x]++;
	}
	dp[0][0][0][0] = a[1];
	for (int i = 0; i <= b[1]; i++) {
		for (int j = 0; j <= b[2]; j++) {
			for (int k = 0; k <= b[3]; k++) {
				for (int z = 0; z <= b[4]; z++) {
					int r = 1 + 1 * i + 2 * j + 3 * k + 4 * z;
					if (i != 0)
						dp[i][j][k][z] = max(dp[i][j][k][z], dp[i - 1][j][k][z] + a[r]);
					if (j != 0)
						dp[i][j][k][z] = max(dp[i][j][k][z], dp[i][j - 1][k][z] + a[r]);
					if (k != 0)
						dp[i][j][k][z] = max(dp[i][j][k][z], dp[i][j][k - 1][z] + a[r]);
					if (z != 0)
						dp[i][j][k][z] = max(dp[i][j][k][z], dp[i][j][k][z - 1] + a[r]);
				}
			}
		}
	}
	printf("%d", dp[b[1]][b[2]][b[3]][b[4]]);
	return 0;
}