P8444 不等价交换法则

https://www.luogu.com.cn/record/80991984

Luogu/P8444/P8444.cpp

@@ -0,0 +1,50 @@
+#include <iostream>
+#include <algorithm>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e6 + 5;
+
+int n;
+long long w;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    std::vector<int> a(n);
+
+    for (int &x : a) {
+        cin >> x;
+    }
+
+    std::sort(a.begin(), a.end());
+
+    cin >> w;
+
+    auto it = std::upper_bound(a.begin(), a.end(), w);
+
+    if (it == a.begin()) {
+        cout << 0 << endl;
+
+        exit(0);
+    } else {
+        it--;
+    }
+
+    int ans = 0;
+    long long sum = 0;
+    for (auto i = a.begin(); i != a.end(); i++) {
+        if ((sum += *i) <= *it) ans++;
+        else break;
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}