new file: B3881.cpp

B3881.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+#define int long long
+using namespace std;
+int n, k, p[1000005];
+signed main() {
+    scanf("%lld%lld%lld", &n, &k, &p[1]);
+    for (int i = 2; i <= k; ++i)
+        p[i] = p[i - 1] + ((p[i - 1] * 7ll + 7) % 10) + 1;
+    sort(p + 1, p + k + 1);
+    int ans = 0;
+    for (int l = 1, r = p[k] - p[1], mid = (l + r) >> 1; l <= r; mid = (l + r) >> 1) {
+        int cnt = 1, lst = p[1];
+        for (int i = 2; i <= k && cnt < n; ++i)
+            if (p[i] - lst >= mid)
+                ++cnt, lst = p[i];
+        if (cnt >= n)
+            ans = mid, l = mid + 1;
+        else
+            r = mid - 1;
+    }
+    printf("%lld\n", ans);
+    return 0;
+}