P3743 kotori的设备

R44571071

Luogu/problem/P3743/P3743.cpp

@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n;
+double p, a[100005], b[100005];
+double sum, l, r = 1e10, mid;
+
+bool check(double mid) {
+    double q = mid * p;
+    sum = 0;
+    for (int i = 0; i < n; i++) {
+        if (a[i] * mid > b[i]) {
+            sum += a[i] * mid - b[i];
+        }
+    }
+    return sum <= q;
+}
+
+int main() {
+    cin >> n >> p;
+    for (int i = 0; i < n; i++) {
+        cin >> a[i] >> b[i];
+        sum += a[i];
+    }
+    if (sum <= p) {
+        cout << -1 << endl;
+        return 0;
+    }
+    while (r - l > 1e-6) {
+        mid = (l + r) / 2;
+        if (check(mid)) {
+            l = mid;
+        } else {
+            r = mid;
+        }
+    }
+    cout << fixed << setprecision(10) << l << endl;
+    return 0;
+}