Add FZOI Codes

FZOI/自然数拆分.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+void f(int n, int r, vector<int>& vt, int start, int count) {
+    if (count == 0) {
+        for (int i = 0; i < vt.size(); i ++ ) {
+            cout << vt[i];
+        }
+        cout << endl;
+    }
+    else {
+        for (int i = start; i >= r; i--) {
+            vt.push_back(i);
+            f(n, r - 1, vt, i - 1, count - 1);
+            vt.pop_back();
+        }
+    }
+}
+
+int main() {
+    int n, r;
+    cin >> n >> r;
+
+    vector<int> vt;
+    f(n, r, vt, n, r);
+
+    int t = 1;
+    for (int i = n; i > n - r; i--) {
+        t *= i;
+    }
+    for (int i = 2; i <= r; i++) {
+        t /= i;
+    }
+
+    cout << "total=" << t << endl;
+
+    return 0;
+}