update

src/8/22/P1297.cpp

@@ -1,3 +1,29 @@
-int main(){
-    
-}
+#include <algorithm>
+#include <cstdio>
+#include <iostream>
+#include <vector>
+
+#define long long long
+
+using namespace std;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    int n;
+    long A, B, C;
+    vector<long> a(10000001);
+    scanf("%d%lld%lld%lld%ld", &n, &A, &B, &C, &a[1]);
+    for (int i = 2; i <= n; ++i) {
+        a[i] = (a[i - 1] * A + B) % 100000001;
+    }
+    for (int i = 1; i <= n; ++i) {
+        a[i] = a[i] % C + 1;
+    }
+    double exp = 0.0;
+    for (int i = 2; i <= n; ++i) {
+        exp += (double)min(a[i - 1], a[i]) / (double)(a[i - 1] * a[i]);
+    }
+    exp += (double)min(a[n], a[1]) / (double)(a[n] * a[1]);
+    printf("%.3f\n", exp);
+}