ZOJ-2996 (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

题目描述：给出n和i，（1+x）^n ，让你求x^i次的系数。

题目思路：很容易想到的是二项式展开，然后求x^i的系数。求C（n,i）的奇偶性偶数输出0，奇数则输出1，由此可以简化代码。C（n,i）的奇偶性有一个性质就是如果为奇数，(n & i) == i。

题目链接：ZOJ 2996

以下是代码：

#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <string>
#include <cstring>
using namespace std;

int main(){
	long long n,i;
	while (cin >> n >> i)
	{
		if ((n & i) == i)
			cout << 1 << endl;
		else
			cout << 0 << endl;	
	}
	return 0;
}