#1971. 【Public NOIP Round #5】青鱼和怪兽

https://sjzezoj.com/submission/72577

S2OJ/1971/1971.cpp

@@ -0,0 +1,54 @@
+#include <iostream>
+#include <iomanip>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1005;
+const double eps = 1e-6;
+
+int n, m, c;
+double p, f[N][N];
+
+bool check(double x) {
+    for (int i = 0; i <= m; i++) {
+        f[0][i] = x;
+    }
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= m; j++) {
+            f[i][j] = std::min(x, f[i - 1][j] * (1.0 - p) + f[i][j - 1] * p + 1);
+        }
+    }
+
+    return f[n][m] < x;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m >> c;
+
+    p = c / 100.0;
+
+    double l = 0,
+           r = 1e9,
+           res = 1e9;
+
+    while (r - l > eps) {
+        double mid = (l + r) / 2;
+
+        if (check(mid)) {
+            r = mid;
+            res = mid;
+        } else {
+            l = mid;
+        }
+    }
+
+    cout << std::fixed << std::setprecision(12) << res << endl;
+
+    return 0;
+}