【dp】P1541 乌龟棋

链接：

https://www.luogu.org/problemnew/show/P1541

【思路】：

用f[a][b][c][d]表示，第一张卡用a张，第二张卡用b张..........然后就盘就ok了

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>
#include<map>
#include<string>
#include<cstring>
using namespace std;
const int maxn=999999999;
const int minn=-999999999;
inline int read() {
    char c = getchar();
    int x = 0, f = 1;
    while(c < '0' || c > '9') {
        if(c == '-') f = -1;
        c = getchar();
    }
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}
int n,m,a[355],f[41][41][41][41],s[305],js[5],b;
int main() {
    cin>>n>>m;
    for(int i=1; i<=n; ++i) {
        a[i]=read();
    }
    for(int i=1; i<=m; ++i) {
        cin>>b;
        js[b]++;
    }
     f[0][0][0][0]=a[1];
    for(int i=0; i<=js[1]; ++i) {
        for(int j=0; j<=js[2]; ++j) {
            for(int k=0; k<=js[3]; ++k) {
                for(int l=0; l<=js[4]; ++l) {
                    int place=1+i*1+j*2+k*3+l*4;
                    if(i!=0) {
                        f[i][j][k][l]=max(f[i][j][k][l],f[i-1][j][k][l]+a[place]);
                    }
                    if(j!=0) {
                        f[i][j][k][l]=max(f[i][j][k][l],f[i][j-1][k][l]+a[place]);
                    }
                    if(k!=0) {
                        f[i][j][k][l]=max(f[i][j][k][l],f[i][j][k-1][l]+a[place]);
                    }
                    if(l!=0) {
                        f[i][j][k][l]=max(f[i][j][k][l],f[i][j][k][l-1]+a[place]);
                    }
                }
            }
        }
    }
    cout<<f[js[1]][js[2]][js[3]][js[4]];
    return 0;
}