func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mxn = 100000;   long long n, k;   int a[2][mxn], first[mxn];   vector<pair<int, int> > v;   void sol() {     cout << k <<   n ;     for (pair<int, int> i : v) cout << (i.first + 1) <<     << i.second <<   n ;     exit(0);   }   void add(int x, int y) {     if (a[0][x + 1] + y < 0 || a[0][x + 1] + y > 9) add(x + 1, -y);     if (v.size() == mxn) sol();     a[0][x] += y, a[0][x + 1] += y;     v.push_back({x, y});   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n;     for (int i = 0; i < 2; i++)       for (int j = 0; j < n; j++) {         char c;         cin >> c;         a[i][j] = c -  0 ;       }     memcpy(first, a[0], sizeof(first));     for (int i = 0; i < n - 1; i++) {       int x = a[1][i] - first[i];       k += abs(x), first[i] += x, first[i + 1] += x;     }     if (a[1][n - 1] != first[n - 1]) k = -1, sol();     for (int i = 0; i < n - 1; i++)       while (a[0][i] != a[1][i]) {         add(i, 2 * (a[0][i] < a[1][i]) - 1);       }     sol();     return 0;   }   