C - 二八定律

XJOI/contest/22a/C/C.cpp

@@ -0,0 +1,43 @@
+#include <algorithm>
+#include <iomanip>
+#include <iostream>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, a[N], sum[N];
+double ans_a, ans_b;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    std::sort(a + 1, a + 1 + n, std::greater<int>());
+
+    for (int i = 1; i <= n; i++) {
+        sum[i] = sum[i - 1] + a[i];
+    }
+
+    ans_a = 100.0 * 1 / n;
+    ans_b = 1.0 * sum[1] * 100 / sum[n];
+
+    for (int i = 2; i <= n; i++) {
+        if (1.0 * sum[i] * 100 / sum[n] - 100.0 * i / n >= ans_b - ans_a) {
+            ans_a = 100.0 * i / n;
+            ans_b = 1.0 * sum[i] * 100 / sum[n];
+        }
+    }
+
+    cout << std::fixed << std::setprecision(2) << ans_a << ' '
+         << std::fixed << std::setprecision(2) << ans_b << endl;
+
+    return 0;
+}