P1541 乌龟棋

30分做法，暴力枚举：

#include <bits/stdc++.h>
using namespace std;
const int maxn = 400;
int n, m;
int a[maxn], b[maxn]; //a:格子，b:卡牌
void read() {
    cin >> n >> m;
    for(int i = 0; i < n; i++) cin >> a[i];
    for(int i = 0; i < m; i++) cin >> b[i];
}
int main() {
    read();
    sort(b, b+m);
    int ans = 0, tmp, pos, i;
    do{
        i = 0;
        tmp = 0;
        pos = 0;
        while(i <= m && pos <= n) {
            tmp += a[pos];
            pos += b[i++];
        }
        ans = max(ans, tmp);
    }while(next_permutation(b, b+m));
    cout << ans;
}

100分做法：dp，f[i][j][k][l]为使用i张1，j张2，k张3，l张4；

开始没有想到这个办法是因为没有注意到条件；

上代码

#include <bits/stdc++.h>
using namespace std;
const int maxn = 355;
const int maxm = 125;
const int maa = 41;
int n, m,one = 0, two = 0, three = 0, four = 0;
int a[maxn], b[maxm]; //a:格子，b:卡牌
void read() {
    cin >> n >> m;
    for(int i = 0; i < n; i++) cin >> a[i];
    for(int i = 0; i < m; i++) {cin >> b[i];
        if(b[i] == 1) one++;
        else if(b[i] == 2) two++;
        else if(b[i] == 3) three++;
        else four++;
    }
}

int main() {
    read();
    int f[maa][maa][maa][maa];
    f[0][0][0][0] = a[0];
    for(int i = 0; i <= one; i++) {
        for(int j = 0; j <= two; j++) {
            for(int k = 0; k <= three; k++) {
                for(int l = 0; l <= four; l++) {
                    int maxx = 0;
                    if(i > 0)maxx = max(maxx, f[i-1][j][k][l]);
                    if(j > 0)maxx = max(maxx, f[i][j-1][k][l]);
                    if(k > 0)maxx = max(maxx, f[i][j][k-1][l]);
                    if(l > 0)maxx = max(maxx, f[i][j][k][l-1]);
                    f[i][j][k][l] = maxx + a[i*1+j*2+k*3+l*4];
                }
            }
        }
    }
    cout << f[one][two][three][four];
}