Educational Codeforces Round 59 (Rated for Div. 2) E. Vasya and Binary String（区间dp）

题目链接：http://codeforces.com/contest/1107/problem/E

#include 
#define pi acos(-1.0 )
#define fastio ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
const int INF = 0x3f3f3f3f;
const LL LL_INF = 0x3f3f3f3f3f3f3f3f;//4e18 ~= 2^62
const int maxn =100 + 10;
const LL mod = 1e9+7;

string s;
LL a[maxn];
LL dp[maxn][maxn][maxn];
LL dfs(int l, int r, int k)
{
    if(l>r) return 0;
    if(l == r) return a[k+1];
    if(dp[l][r][k] != -1) return dp[l][r][k];
    dp[l][r][k] = dfs(l,r-1, 0) + a[k+1];
    for(int i=l; i<r; i++){
        if(s[i] == s[r]){
            dp[l][r][k] = max(dp[l][r][k], dfs(l, i, k+1) + dfs(i+1, r-1, 0));
        }
    }
    return dp[l][r][k];
}

int main()
{
    int n;
    scanf("%d", &n);
    cin >> s;
    for(int i=1; i<=n; i++){
        scanf("%I64d", &a[i]);
    }
    memset(dp, -1, sizeof(dp));
    printf("%I64d\n", dfs(0, n-1, 0));
}