Need help with this string problem

given a binary string s having length N*N. N is even.number of 1s in the string is equal to number of 0s in the have to rearrange the string in the minimum possible swaps to make the string satisfy the following conditions,

1.if (i+1)%N - i%N =1 then s[i]+s[i+1] =1

2.if i+N < N*N then s[i]+s[i+1]=1

(assume 0 based indexing).

i have tried doing it by creating a temporary string satisfying the conditions and greedily checked each element of s with the temporary string and the answer would be difference count/2. why is this wrong?

example if string s= 1100

temporary string t=1001

difference count=2