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 14 2

Sample Output

10

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;elsecout << 0 << endl;}return 0;}