A bunch new problems

Educational Codeforces Round 177 (Rated for Div. 2)/D. Even String.cpp

@@ -0,0 +1,151 @@
+/* Problem URL: https://codeforces.com/problemset/problem/2086/D */
+
+#include <bits/stdc++.h>
+#include <ext/pb_ds/assoc_container.hpp>
+#include <ext/pb_ds/tree_policy.hpp>
+
+using namespace std;
+using namespace __gnu_pbds;
+
+template <class T, class comp = less<>>
+using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;
+
+#define V vector
+
+#define rmin(a, b) a = min(a, b)
+#define rmax(a, b) a = max(a, b)
+
+#define rep(i, lim) for (int i = 0; i < (lim); i++)
+#define nrep(i, s, lim) for (int i = s; i < (lim); i++)
+
+#define repv(i, v) for (auto &i : (v))
+#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
+#define sortv(v) sort(v.begin(), v.end())
+#define all(v) (v).begin(), (v).end()
+
+using vi = vector<int>;
+using vvi = vector<vi>;
+using vvvi = vector<vvi>;
+using vvvvi = vector<vvvi>;
+
+using ll = long long;
+
+using vl = vector<ll>;
+using vvl = vector<vl>;
+using vvvl = vector<vvl>;
+using vvvvl = vector<vvvl>;
+
+template<class v>
+auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
+    os << vec[0];
+    for (size_t i = 1; i < vec.size(); i++) {
+        os << ' ' << vec[i];
+    }
+    os << '\n';
+    return os;
+}
+
+template<class v>
+auto operator>>(istream &is, vector<v> &vec)->istream& {
+    for (auto &i : vec) {
+        is >> i;
+    }
+    return is;
+}
+
+template<class v>
+auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
+    for (auto &i : vec) {
+        os << i[0];
+        for (size_t j = 1; j < i.size(); j++) {
+            os << ' ' << i[j];
+        }
+        os << '\n';
+    }
+    return os;
+}
+
+template<class v>
+auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
+    for (auto &i : vec) {
+        for (auto &j : i) {
+            is >> j;
+        }
+    }
+    return is;
+}
+
+const int oo = INT32_MAX >> 1;
+const ll OO = INT64_MAX >> 1;
+
+
+const ll mod = 998244353;
+
+constexpr int MAXN = 1e6;
+ll fact[MAXN];
+
+void pre()
+{
+    fact[0] = 1;
+    nrep(i, 1, MAXN) {
+        fact[i] = (fact[i - 1] * i) % mod;
+    }
+}
+
+#define TEST 1
+
+void solve()
+{
+    vi c(26);
+    int s = 0;
+    ll mu = 1;
+    repv(i, c) {
+        cin >> i;
+        s += i;
+        mu *= fact[i];
+        mu %= mod;
+    }
+
+    int o = (s + 1) >> 1;
+
+    vi dp(o + 1);
+    dp[0] = 1;
+    rep(i, 26) {
+        if (c[i] == 0) {
+            continue;
+        }
+
+        for (int j = o; j >= c[i]; j--) {
+            dp[j] += dp[j - c[i]];
+            dp[j] %= mod;
+        }
+    }
+
+    auto fpow = [&](ll a, ll p) {
+        ll ans = 1;
+        rep(i, 61) {
+            if ((p >> i) & 1) {
+                ans = (ans * a) % mod;
+            }
+            a = (a * a) % mod;
+        }
+
+        return ans;
+    };
+
+    cout << fact[o] * fact[s >> 1] % mod * fpow(mu, mod - 2) % mod * dp[o] % mod << '\n';
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    pre();
+
+    int t;
+    (TEST && cin >> t) || (t = 1);
+    while (t--) {
+        solve();
+    }
+}