例题：acwing900整数划分

完全背包解法

#include <iostream>
#include <algorithm>using namespace std;const int N = 1010, mod = 1e9 + 7;int n;
int f[N];int main()
{cin >> n;f[0] = 1;for (int i = 1; i <= n; i ++ )for (int j = i; j <= n; j ++ )f[j] = (f[j] + f[j - i]) % mod;cout << f[n] << endl;return 0;
}

其他解法

#include <iostream>
#include <algorithm>using namespace std;const int N = 1010, mod = 1e9 + 7;int n;
int f[N][N];int main()
{cin >> n;f[1][1] = 1;for (int i = 2; i <= n; i ++ )for (int j = 1; j <= i; j ++ )f[i][j] = (f[i - 1][j - 1] + f[i - j][j]) % mod;int res = 0;for (int i = 1; i <= n; i ++ ) res = (res + f[n][i]) % mod;cout << res << endl;return 0;
}