From e676c04e15bad4c2e083c8761a4d115653675591 Mon Sep 17 00:00:00 2001
From: Ren Baoshuo <i@baoshuo.ren>
Date: Mon, 21 Sep 2020 19:48:40 +0800
Subject: [PATCH] =?UTF-8?q?P4994=20=E7=BB=88=E4=BA=8E=E7=BB=93=E6=9D=9F?=
 =?UTF-8?q?=E7=9A=84=E8=B5=B7=E7=82=B9?=
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R38706118
---
 problem/P4994/P4994.cpp | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 problem/P4994/P4994.cpp

diff --git a/problem/P4994/P4994.cpp b/problem/P4994/P4994.cpp
new file mode 100644
index 00000000..330dfc99
--- /dev/null
+++ b/problem/P4994/P4994.cpp
@@ -0,0 +1,37 @@
+// R38706118
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+long long a[10000000];
+
+long long dfib(long long x, long long m) {
+    if (a[x] != -1) {
+        return a[x];
+    }
+    if (x == 0) {
+        a[x] = 0 % m;
+        return 0;
+    }
+    if (x == 1) {
+        a[x] = 1 % m;
+        return 1;
+    }
+    a[x] = (dfib(x - 1, m) + dfib(x - 2, m)) % m;
+    return a[x];
+}
+
+int main() {
+    long long m;
+    memset(a, 0xff, sizeof(a));
+    cin >> m;
+    for (int i = 2; i < m * m; i++) {
+        // cout << i << ' ' << dfib(i, m) << endl;
+        if (dfib(i, m) == 0 && dfib(i + 1, m) == 1) {
+            cout << i;
+            break;
+        }
+    }
+    return 0;
+}