The 2025 ICPC Northern Eurasia Finals

Author: Macesuted

QOJ/15899.cpp

@@ -0,0 +1,64 @@
+/**
+ * @file 15899.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-01-20
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+#define maxn 500005
+
+int64_t a[maxn], f[maxn];
+
+void solve(void) {
+    int n;
+    cin >> n;
+    for (int i = 1; i <= n; i++) cin >> a[i];
+
+    f[1] = a[1], f[n] = 0;
+    for (int i = 2; i < n; i++) f[i] = a[i] - f[i - 1];
+
+    if (n & 1) {
+        int64_t x = (a[n] - f[n - 1]) / 2;
+        for (int i = 1; i < n; i++) f[i] += (i & 1) ? -x : +x;
+        f[n] += x;
+
+        int64_t maxv = INT64_MIN, sum = 0;
+        for (int i = 1; i <= n; i++) maxv = max(maxv, f[i]), sum += f[i];
+        cout << max(maxv, sum / (n - 1) + (sum % (n - 1) > 0)) << endl;
+
+        return;
+    }
+
+    int64_t maxu = INT64_MIN, minu = INT64_MAX, maxd = INT64_MIN, mind = INT64_MAX, sum = 0;
+    for (int i = 1; i <= n; i += 2) maxd = max(maxd, f[i]), mind = min(mind, f[i]), sum += f[i];
+    for (int i = 2; i <= n; i += 2) maxu = max(maxu, f[i]), minu = min(minu, f[i]), sum += f[i];
+
+    int64_t ans = INT64_MAX;
+    int64_t X = max(min((maxd - maxu) / 2, mind), -minu);
+    for (int64_t x = X - 10; x <= X + 10; x++) {
+        if (mind - x < 0 || minu + x < 0) continue;
+        int64_t maxv = max(maxd - x, maxu + x);
+        ans = min(ans, max(maxv, sum / (n - 1) + (sum % (n - 1) > 0)));
+    }
+
+    cout << ans << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    cin >> _;
+    while (_--) solve();
+
+    return 0;
+}

QOJ/15900.cpp

@@ -0,0 +1,56 @@
+/**
+ * @file 15900.cpp
+ * @author Macesuted (i@macesuted.moe)
+ * @date 2026-01-20
+ *
+ * @copyright Copyright (c) 2026
+ *
+ */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define endl '\n'
+
+multiset<int> split(int n) {
+    multiset<int> S;
+    for (int i = 2; i * i <= n; i++)
+        while (n % i == 0) S.insert(i), n /= i;
+    if (n > 1) S.insert(n);
+    return S;
+}
+
+void solve(void) {
+    int w, h, d, n;
+    cin >> w >> h >> d >> n;
+
+    multiset<int> Sw = split(w), Sh = split(h), Sn = split(n);
+
+    int wc = 1, hc = 1, dc = 1;
+    for (auto i = Sn.begin(); i != Sn.end();)
+        if (Sw.count(*i))
+            Sw.erase(Sw.find(*i)), wc *= *i, i = Sn.erase(i);
+        else
+            i++;
+    for (auto i = Sn.begin(); i != Sn.end();)
+        if (Sh.count(*i))
+            Sh.erase(Sh.find(*i)), hc *= *i, i = Sn.erase(i);
+        else
+            i++;
+    dc = n / wc / hc;
+
+    if (d % dc) return cout << -1 << endl, void();
+
+    cout << wc - 1 << ' ' << hc - 1 << ' ' << dc - 1 << endl;
+
+    return;
+}
+
+int main() {
+    ios::sync_with_stdio(false), cin.tie(nullptr);
+
+    int _ = 1;
+    while (_--) solve();
+
+    return 0;
+}