func_code_string: #include<bits/stdc++.h>   using namespace std;      int main(){       int t;       cin>>t;              while(t--){           int n;           cin>>n;                      int A[n],B[n];           vector<int>pos,neg;           for(int i=0;i<n;++i){               cin>>A[i];           }                      int z=0;           int m=0;           for(int i=0;i<n;++i){               cin>>B[i];               z+=(B[i]-A[i]);               if(B[i]>A[i]){                   m+=(B[i]-A[i]);                   neg.push_back(i);               }               if(B[i]<A[i]){                   pos.push_back(i);               }           }                      if(z==0){                               cout<<m<<  n ;               int i1=0,i2=0;               for(int i=0;i<m;++i){                   cout<<(pos[i1]+1)<<   <<(neg[i2]+1)<<  n ;                   A[pos[i1]]--;                   A[neg[i2]]++;                                      if(A[pos[i1]]==B[pos[i1]])i1++;                   if(A[neg[i2]]==B[neg[i2]])i2++;               }           }           else{               cout<< -1 n ;           }                  }   }