27 lines
870 B
Ruby
27 lines
870 B
Ruby
|
#Given array of integers(both +ve and -ve) find the two elements such that their sum is closest to given number x.
|
||
|
|
#Time-complexity: O(nlogn) // O(nlogn){for sorting}+O(n), Auxiliary-space:O(1)
|
||
|
|
|
||
|
|
#Algorithm: Sort the array and using two indexes left and right update the closest sum
|
||
|
|
|
||
|
|
def closest_sum(a,x)
|
||
|
|
a.sort! #You can choose any sorting algorithm of your choice with
|
||
|
|
left=min_l=0
|
||
|
|
right=min_r=a.length-1
|
||
|
|
min_sum = 1.0/0.0 #Initializing min_sum with infinity
|
||
|
|
while(left<right)
|
||
|
|
sum=(a[left]+a[right])-x
|
||
|
|
if sum.abs<min_sum
|
||
|
|
min_sum=sum.abs
|
||
|
|
min_l=left
|
||
|
|
min_r=right
|
||
|
|
end
|
||
|
|
if sum<0
|
||
|
|
left+=1
|
||
|
|
else
|
||
|
|
right-=1
|
||
|
|
end
|
||
|
|
end
|
||
|
|
print " The two elements whose sum is minimum are #{a[min_l]} and #{a[min_r]}"
|
||
|
|
end
|
||
|
|
|
||
|
|
closest_sum([1,3,2,4,5],9) # => The two elements whose sum is minimum are 4 and 5
|