func_code_string: #include<bits/stdc++.h>   #define ll long long   #define ull unsigned long long      #define  in(ar,n) for(int i=0;i<n;i++)cin>>ar[i];   #define invec(ar,n)for(int i  =0 ; i<n;i++){int temp;cin>>temp;ar.push_back(temp);}   #define in2d(ar,n,m) for(int i=0;i<n;i++)for(int i=0;i<m;i++)cin>>ar[i]   #define out(ar,n)     for(int i=0;i<n;i++)     cout<<ar[i]<<   ;     cout<<endl;   #define swap(a,b)    int t = a;     a = b;     b = t;   #define print(val) cout<<val<<endl;   #define set(ar,n,val) for(int i=0;i<n;i++)ar[i]=val   #define for2d(n,m) for(int i=0;i<n;i++)for(int j=0;j<m;j++)   #define minar(ar,n,mn) for(int i=0;i<n;i++)mn =min(mn,ar[i])   #define maxar(ar,n,mx) for(int i=0;i<n;i++)mx =max(mx,ar[i])   #define fori(i,a,b) for(ll i=a;i<b;++i)   #define all(ar) ar.begin(),ar.end()   using namespace std;   typedef pair<ll,ll> pll;   typedef pair<int,int> pii;   typedef vector<vector<int>> vvi;   const ll mod = 1e9 + 7;      int main(){       int t;cin>>t;       while(t--){          int n;cin>>n;          string s;cin>>s;          vector<int> ar,ans;          fori(i,0,n){              ar.push_back(s[i]- 0 );             }           ans.push_back(1);          int c = ar[0]+1;             fori(i,1,n){              if(c==2){                  if(ar[i]==1){                      ans.push_back(0);                      c = 1;                  }                  else {                      ans.push_back(1);                      c = 1;                  }              }              else if(c==1){                  if(ar[i]==1){                      ans.push_back(1);                       c = 2;                  }                  else {ans.push_back(0);c = 0;}              }              else {                  if(ar[i]==0){                      ans.push_back(1);                      c = 1;                  }                  else {                      ans.push_back(1);                      c = 2;                  }              }          }          fori(i,0,n){              cout<<ans[i];          }          cout<<endl;       }   }