This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <iostream>
#include <map>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
template <typename T>
using ve = vector<T>;
const int N = 2505;
const ll B = 137, M = 1000000007;
int n, lcp[N][N];
ll dp[N][N], a, b, c;
char s[N];
ll hs[N], bp[N], ibp[N];
ll bpow(ll a, ll b) {
    if (!b) return 1;
    ll r { bpow(a, b / 2) };
    if (b & 1) return r * r % M * a % M;
    return r * r % M;
}
void do_hash() {
    bp[0] = ibp[0] = 1;
    for (int i = 1; i <= n; ++i) bp[i] = bp[i - 1] * B % M, ibp[i] = bpow(bp[i], M - 2);
    for (int i = 1; i <= n; ++i) hs[i] = bp[i] * s[i] % M, hs[i] = (hs[i] + hs[i - 1]) % M;
}
ll get_hash(int l, int r) {
    return ibp[l] * (hs[r] - hs[l - 1] + M) % M;
}
map<ll, ve<int>> oo, op[N];
int main() {
    scanf("%d%s%lld%lld%lld", &n, s + 1, &a, &b, &c);
    do_hash();
    memset(dp, 63, sizeof dp);
    map<int,int>L,R;
    for (int i = 1; i <= n; ++i) {
        dp[i][i] = a;
        for (int j = i; j <= n; ++j) {
            oo[get_hash(i, j)].push_back(i);
        L[get_hash(i,j)]=i;
        R[get_hash(i,j)]=j;
        }
    }
    for (int i = 1; i <= n; ++i) {
        for (int j = i; j <= n; ++j) {
            ll x = get_hash(i, j);
            auto &v = oo[x];
            auto it = lower_bound(v.begin(), v.end(), i);
            while (it != v.end()) {
                op[i][x].push_back(*it);
                it = lower_bound(v.begin(), v.end(), *it + j - i + 1);
            }
        }
    }
    ll ssi = get_hash(3, 5);
    for (int l = 2; l <= n; ++l) {
        for (int i = 1, j = l; j <= n; ++i, ++j) {
            for (int k = i; k <= j; ++k) {
                int len = k - i + 1;
                ll x = get_hash(i, k);
                auto &oc = op[i][x];
                int cnt = upper_bound(oc.begin(), oc.end(), j - len + 1) - lower_bound(oc.begin(), oc.end(), i);
                int lef = l - cnt * len;
                dp[i][j] = min(dp[i][j], dp[i][k] + lef * a + cnt * c + b);
            }
            dp[i][j] = min(dp[i][j], dp[i + 1][j] + a);
        }
    }
    printf("%lld", dp[1][n]);
}
Compilation message (stderr)
copypaste3.cpp: In function 'int main()':
copypaste3.cpp:67:8: warning: unused variable 'ssi' [-Wunused-variable]
   67 |     ll ssi = get_hash(3, 5);
      |        ^~~
copypaste3.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |     scanf("%d%s%lld%lld%lld", &n, s + 1, &a, &b, &c);
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