Write a function max_sum that takes v a row vector of numbers & n,a positive integer as inputs.The function needs to find n consecutive elements of v whose sum is largest poss

I write this code for the qst in desciption

function [summa,index] =  max_sum(v,n)
l=length(v); 
if n>length(v)
    summa =0
    index=-1
else
      m=v(1:n)
      for ii=1:l-n+1
             vect=v(ii:ii+n-1)
            
             if sum(m)<sum(vect)
              m=vect

             end

      end
               summa = sum(m)
              index = m(1)
              
end
end

and it's working for all exemple in description but for long vector like in qst 2 the result it's false

the problem is the rihjt response it's my, bcz I check it and I don't know if someone can help me if I already didn't undestand the problem

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/526597-write-a-function-max_sum-that-takes-v-a-row-vector-of-numbers-n-a-positive-integer-as-inputs-the-f?s_tid=srchtitle

Answer 1

[Divyam]

Hi @malki adil,

You can use the 'conv' function to compute the sum of every window of length n efficienty:

function [sum, idx] = max_sum(v, n) 
% Finds n consecutive elements in v with the largest sum. 
    if n > length(v) 
        error('n must not exceed the length of v'); 
    end 
    s = conv(v, ones(1, n), 'valid'); 
    % Sliding sum 
    [sum, idx] = max(s); 
end 

v = [1 3 2 5 6 2 1]; 
n = 3; 
[sum, idx] = max_sum(v, n)

sum = 13

idx = 3

For more information regarding the 'conv' function, refer to the following documentation: https://www.mathworks.com/help/matlab/ref/conv.html