CF639C.Bear and Polynomials

普及/提高-

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题目描述

Limak is a little polar bear. He doesn't have many toys and thus he often plays with polynomials.

He considers a polynomial valid if its degree is nn and its coefficients are integers not exceeding kk by the absolute value. More formally:

Let a0,a1,...,ana_{0},a_{1},...,a_{n} denote the coefficients, so . Then, a polynomial P(x)P(x) is valid if all the following conditions are satisfied:

  • aia_{i} is integer for every ii ;
  • ai<=k|a_{i}|<=k for every ii ;
  • an0a_{n}≠0 .

Limak has recently got a valid polynomial PP with coefficients a0,a1,a2,...,ana_{0},a_{1},a_{2},...,a_{n} . He noticed that P(2)0P(2)≠0 and he wants to change it. He is going to change one coefficient to get a valid polynomial QQ of degree nn that Q(2)=0Q(2)=0 . Count the number of ways to do so. You should count two ways as a distinct if coefficients of target polynoms differ.

输入格式

The first line contains two integers nn and kk ( 1<=n<=200000,1<=k<=1091<=n<=200000,1<=k<=10^{9} ) — the degree of the polynomial and the limit for absolute values of coefficients.

The second line contains n+1n+1 integers a0,a1,...,ana_{0},a_{1},...,a_{n} ( ai<=k,an0|a_{i}|<=k,a_{n}≠0 ) — describing a valid polynomial . It's guaranteed that P(2)0P(2)≠0 .

输出格式

Print the number of ways to change one coefficient to get a valid polynomial QQ that Q(2)=0Q(2)=0 .

输入输出样例

  • 输入#1

    3 1000000000
    10 -9 -3 5
    

    输出#1

    3
    
  • 输入#2

    3 12
    10 -9 -3 5
    

    输出#2

    2
    
  • 输入#3

    2 20
    14 -7 19
    

    输出#3

    0
    

说明/提示

In the first sample, we are given a polynomial P(x)=109x3x2+5x3P(x)=10-9x-3x^{2}+5x^{3} .

Limak can change one coefficient in three ways:

  1. He can set a0=10a_{0}=-10 . Then he would get Q(x)=109x3x2+5x3Q(x)=-10-9x-3x^{2}+5x^{3} and indeed Q(2)=101812+40=0Q(2)=-10-18-12+40=0 .
  2. Or he can set a2=8a_{2}=-8 . Then Q(x)=109x8x2+5x3Q(x)=10-9x-8x^{2}+5x^{3} and indeed Q(2)=101832+40=0Q(2)=10-18-32+40=0 .
  3. Or he can set a1=19a_{1}=-19 . Then Q(x)=1019x3x2+5x3Q(x)=10-19x-3x^{2}+5x^{3} and indeed Q(2)=103812+40=0Q(2)=10-38-12+40=0 .

In the second sample, we are given the same polynomial. This time though, kk is equal to 1212 instead of 10910^{9} . Two first of ways listed above are still valid but in the third way we would get |a_{1}|>k what is not allowed. Thus, the answer is 22 this time.

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