目录调整

00lanqiao chap/test99-4-4.cpp

@@ -0,0 +1,23 @@
+// 斐波那契数递归优化
+#include<bits/stdc++.h>
+using namespace std;
+using ll = long long;
+const ll p = 1e9+7;
+const int inf = 1e9, N = 1e5+3;
+ll dp[N];
+ll f(int n){
+    if( n <= 2) return 1;
+    if(dp[n] != -1) return dp[n];
+
+    return dp[n] = (f(n -1 ) + f(n - 2)) % p;
+}
+
+int main(){
+    memset(dp, -1, sizeof dp);
+    int n; cin >> n;
+    cout << f(n) << endl;
+    return 0;
+} 
+/* test samples 976496506
+5000 
+*/