103563: [Atcoder]ABC356 D - Masked Popcount

Memory Limit:256 MB Time Limit:2 S
Judge Style:Text Compare Creator:
Submit:8 Solved:0

Description

Score : $400$ points

Problem Statement

Given integers $N$ and $M$, compute the sum $\displaystyle \sum_{k=0}^{N}$ $\rm{popcount}$$(k \mathbin{\&} M)$, modulo $998244353$.

Here, $\mathbin{\&}$ represents the bitwise $\rm{AND}$ operation.

What is the bitwise $\rm{AND}$ operation? The result $x = a \mathbin{\&} b$ of the bitwise $\rm{AND}$ operation between non-negative integers $a$ and $b$ is defined as follows:
  • $x$ is the unique non-negative integer that satisfies the following conditions for all non-negative integers $k$:
    • If the $2^k$ place in the binary representation of $a$ and the $2^k$ place in the binary representation of $b$ are both $1$, then the $2^k$ place in the binary representation of $x$ is $1$.
    • Otherwise, the $2^k$ place in the binary representation of $x$ is $0$.
For example, $3=11_{(2)}$ and $5=101_{(2)}$, so $3 \mathbin{\&} 5 = 1$.
What is $\rm{popcount}$? $\rm{popcount}$$(x)$ represents the number of $1$s in the binary representation of $x$.
For example, $13=1101_{(2)}$, so $\rm{popcount}$$(13) = 3$.

Constraints

  • $N$ is an integer between $0$ and $2^{60} - 1$, inclusive.
  • $M$ is an integer between $0$ and $2^{60} - 1$, inclusive.

Input

The input is given from Standard Input in the following format:

$N$ $M$

Output

Print the answer as an integer.


Sample Input 1

4 3

Sample Output 1

4
  • $\rm{popcount}$$(0\mathbin{\&}3) = 0$
  • $\rm{popcount}$$(1\mathbin{\&}3) = 1$
  • $\rm{popcount}$$(2\mathbin{\&}3) = 1$
  • $\rm{popcount}$$(3\mathbin{\&}3) = 2$
  • $\rm{popcount}$$(4\mathbin{\&}3) = 0$

The sum of these values is $4$.


Sample Input 2

0 0

Sample Output 2

0

It is possible that $N = 0$ or $M = 0$.


Sample Input 3

1152921504606846975 1152921504606846975

Sample Output 3

499791890

Remember to compute the result modulo $998244353$.

Output

得分:400分

问题描述

给定整数 $N$ 和 $M$,计算和 $\displaystyle \sum_{k=0}^{N}$ $\rm{popcount}$$(k \mathbin{\&} M)$,对 $998244353$ 取模。

其中,$\mathbin{\&}$ 代表位与操作。

位与操作是什么? 位与操作是非负整数 $a$ 和 $b$ 之间的运算,其结果 $x = a \mathbin{\&} b$ 定义如下:
  • $x$ 是唯一满足以下条件的非负整数,对于所有非负整数 $k$:
    • 如果 $a$ 的二进制表示中第 $2^k$ 位和 $b$ 的二进制表示中第 $2^k$ 位都是 $1$,那么 $x$ 的二进制表示中第 $2^k$ 位是 $1$。
    • 否则,$x$ 的二进制表示中第 $2^k$ 位是 $0$。
什么是 $\rm{popcount}$? $\rm{popcount}$$(x)$ 表示整数 $x$ 的二进制表示中 $1$ 的个数。
例如,$13=1101_{(2)}$,所以 $\rm{popcount}$$(13) = 3$。

约束条件

  • $N$ 是在 $0$ 到 $2^{60} - 1$ 之间(含)的整数。
  • $M$ 是在 $0$ 到 $2^{60} - 1$ 之间(含)的整数。

输入

输入从标准输入中以以下格式给出:

$N$ $M$

输出

以整数形式打印答案。


样例输入 1

4 3

样例输出 1

4
  • $\rm{popcount}$$(0\mathbin{\&}3) = 0$
  • $\rm{popcount}$$(1\mathbin{\&}3) = 1$
  • $\rm{popcount}$$(2\mathbin{\&}3) = 1$
  • $\rm{popcount}$$(3\mathbin{\&}3) = 2$
  • $\rm{popcount}$$(4\mathbin{\&}3) = 0$

这些值的和是 $4$。


样例输入 2

0 0

样例输出 2

0

可能出现 $N = 0$ 或 $M = 0$ 的情况。


样例输入 3

1152921504606846975 1152921504606846975

样例输出 3

499791890

记得对结果取模 $998244353$。

加入题单

上一题 下一题 算法标签: