开始计概A下半学期。

pojcs101_T04117_split_int.cpp

@@ -3,18 +3,19 @@
 
 using namespace std;
 
-constexpr int MAX_N = 100;
-int cache[MAX_N * MAX_N];
+constexpr int MAX_N = 5001, MOD = 1e9 + 7;
+long long cache[MAX_N * MAX_N + MAX_N];
 
-int get_split_solutions_count(int n, int parts_count) {
+long long get_split_solutions_count(int n, int parts_count) {
     if (n <= 0 || parts_count > n) { return 0; }
     if (parts_count == 1 || parts_count == n) { return 1; }
     if (cache[n * MAX_N + parts_count] != 0) {
         return cache[n * MAX_N + parts_count];
     }
-    int ans = 0;
+    long long ans = 0;
     for (int i = 1; i <= n / 2; i++) {
         ans += get_split_solutions_count(n - i - (i - 1) * (parts_count - 1), parts_count - 1);
+        ans %= MOD;
     }
     cache[n * MAX_N + parts_count] = ans;
     return ans;
@@ -27,9 +28,10 @@ int main() {
     int n;
     while (cin >> n) {
         // cout << get_split_solutions_count(n, 2) << endl;
-        int ans = 0;
+        long long ans = 0;
         for (int i = 1; i <= n; i++) {
             ans += get_split_solutions_count(n, i);
+            ans %= MOD;
             // clog << i << ":" << ans << " ";
         }
         cout << ans << endl;