7 (1+x)^n

(1+x)^n


Time Limit: 2 Seconds      Memory Limit: 65536 KB


Please calculate the coefficient modulo 2 of x^i in (1+x)^n.

Input

For each case, there are two integers n, i (0<=i<=n<=2^31-1)

Output

For each case, print the coefficient modulo 2 of x^i in (1+x)^n on a single line.

Sample Input

3 1
4 2

Sample Output

1
0

也就是将(1+x)的n次幂展开,在展开式中的每一次项寻找x的i次幂的那一项,然后再让这一项的系数%2(模2),

对于组合数C(n,m),如果(n&m)==m,那么该组合数是奇数,否则为偶数。

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
int main(){
	int n,i;
	while(scanf("%d%d",&n,&i) != EOF){
		printf("%d\n",n&i%2);
	}
}

猜你喜欢

转载自blog.csdn.net/jiuweideqixu/article/details/87888444