238. Product of Array Except Self

Given an array of n integers where n > 1,

nums

, return an array

output

such that

output[i]

is equal to the product of all the elements of

nums

except

nums[i]

.

Solve it without division and in O(n).

For example, given

[1,2,3,4]

, return

[24,12,8,6]

.

Follow up:

Could you solve it with constant space complexity? (Note: The output array
does not count as extra space for the purpose of space complexity analysis.)

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class Solution {
public:
vector<int> productExceptSelf(vector<int>& nums) {
set<int> zeros;
vector<int> v1(nums.size(),0);
double mm=1;
for(int i=0;i<nums.size();++i)
{
if(nums[i]==0)
zeros.insert(i);
else
mm*=nums[i];
}
if(zeros.size()>1) return v1;
if(zeros.size()==1)
{
v1[*(zeros.begin())]=mm;
return v1;
}
for(int i=0;i<nums.size();++i)
{

v1[i]=mm/nums[i];
}
return v1;
}
};

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