# Program to find minimum operations needed to make two arrays sum equal in Python

PythonServer Side ProgrammingProgramming

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Suppose we have two lists nums1 and nums2 where each element in both of the lists in range 1 to 6. Now consider an operation by which, we can select a number from nums1 or nums2 and update its value to a number between 1 to 6. We have to find the minimum number of operations needed so that the sum of these two arrays are same. If we cannot find any solution, return -1.

So, if the input is like nums1 = [1, 4] nums2 = [5, 4, 4], then the output will be 2, because we can make 1 from nums1 to 6, so sum of nums1 is 10, then change any one 4 from nums2 to 1, so its sum is 10 also

To solve this, we will follow these steps −

• sa := sum of all elements present in nums1

• sb := sum of all elements present in nums2

• if sa > sb, then

• swap nums1 and nums2

• swap sa and sb

• sort the list nums1

• sort the list nums2 in reverse order

• res := 0

• toadd := sb - sa

• i := 0, j := 0

• while toadd > 0, do

• res := res + 1

• if i < size of nums1 and j < size of nums2, then

• resa := 6 - nums1[i]

• resb := nums2[j] - 1

• if resa > resb, then

• i := i + 1

• otherwise,

• j := j + 1

• otherwise when i < size of nums1, then

• resa := 6 - nums1[i]

• i := i + 1

• otherwise when j < size of nums2, then

• resb := nums2[j] - 1

• j := j + 1

• otherwise,

• return -1

• return res

## Example

Let us see the following implementation to get better understanding

def solve(nums1, nums2):
sa = sum(nums1)
sb = sum(nums2)
if sa > sb:
nums1, nums2 = nums2, nums1
sa, sb = sb, sa

nums1.sort()
nums2.sort(reverse=True)
res = 0
toadd = sb - sa
i = 0
j = 0
while toadd > 0:
res += 1
if i < len(nums1) and j < len(nums2):
resa = 6 - nums1[i]
resb = nums2[j] - 1
if resa > resb:
i += 1
else:
j += 1
elif i < len(nums1):
resa = 6 - nums1[i]
i += 1
elif j < len(nums2):
resb = nums2[j] - 1
j += 1
else:
return -1

return res

nums1 = [1, 4]
nums2 = [5, 4, 4]
print(solve(nums1, nums2))

## Input

[2,1,4,3,5,4]


## Output

2