[Swust OJ 247]--皇帝的新衣(组合数+Lucas定理)

 1 #include <iostream>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define maxn 405
 5 using namespace std;
 6 long long dp[maxn][maxn], n, m, p;
 7 long long Lucas(long long n, long long m, long long p){
 8     //Lucas定理
 9     if (n <= p && m <= p)
10         return dp[n][m];
11     else
12         return (Lucas(n / p, m / p, p)*dp[n%p][m%p]) % p;
13 }
14 
15 //杨辉三角求组合数
16 void init(){
17     int i, left, right;
18     for (i = 1; i <= p; i++){
19         dp[i][0] = dp[i][i] = 1;
20         left = 1, right = i - 1;
21         while (left <= right){
22             dp[i][left] = (dp[i - 1][left - 1] + dp[i - 1][left]) % p;
23             dp[i][right--] = dp[i][left++];//组合数性质dp[i][j]=dp[i][i-j];
24         }
25     }
26 }
27 int main(){
28     while (cin >> n >> m >> p && n && m && p){
29         memset(dp, 0, sizeof(dp));
30         init();
31         cout << Lucas(n + m, min(n, m), p) << endl;
32     }
33     return 0;
34 }

 1 import java.math.*;
 2 import java.io.*;
 3 import java.util.*;
 4 public class Main{
 5     static int DP[][] = new int[401][401];
 6     static int p;
 7     public static void main(String[] args)
 8     {
 9         Scanner cin = new Scanner(System.in);
10         int a, b;
11         while (cin.hasNext()){
12             a = cin.nextInt();
13             b = cin.nextInt();
14             p = cin.nextInt();
15             if (a == 0)
16                 break;
17             initDp();
18             System.out.println(sloveRe(a + b, b > a ? a : b));
19         }
20     }
21     private static void initDp(){
22         int i, j;
23         for (i = 0; i <= p; i++){
24             DP[i][0] = 1;
25         }
26         for (i = 1; i <= p; i++){
27             for (j = 1; j <= p; j++){
28                 DP[i][j] = (DP[i - 1][j] + DP[i - 1][j - 1]) % p;
29             }
30         }
31     }
32     private static int sloveRe(int n, int m){
33         if (n <= p&&m <= p)
34             return DP[n][m];
35         else
36             return  (sloveRe(n / p, m / p)*DP[n%p][m%p]) % p;
37     }
38 }