组合数公式+前缀和

#include <iostream>
#include <stdio.h>
#include <string.h>
#include <algorithm>
#define maxn 2100
#define int long long
#define Int signed
using namespace std ;
int n , m , k , T , C[maxn][maxn] , s[maxn][maxn] ;
Int main () {
	cin >> T >> k ;
	for(int i = 0 ; i <= 2000 ; i ++) {
		C[i][i] = C[i][0] = 1 ;
	} //C[1][1] = 1 ;
	for(int i = 0 ; i <= 2000 ; i ++) {
		for(int j = 1 ; j <= i ; j ++) {
			C[i][j] = (C[i-1][j] + C[i-1][j-1])%k ;
		}
	}
	for(int i = 2 ; i <= 2000 ; i ++) {
		for(int j = 1 ; j <= i ;j ++) {
			s[i][j] = s[i-1][j] + s[i][j-1] - s[i-1][j-1] ;
			if(C[i][j] == 0) {
				s[i][j] ++ ;
			} 
		}s[i][i+1] = s[i][i] ;
	}
	while(T --) {
		cin >> n >> m ;
		cout << s[n][min(n,m)]<<endl ;
	}
	return 0 ;
}