Числа

/// https://informatics.msk.ru/mod/statements/view3.php?chapterid=2001#1
#include <bits/stdc++.h>

using namespace std;

int main(){
    int start, finish;
    cin >> start >> finish;
    queue < int > q;

    int used[10000], dist[10000], from[10000];
    for (int i=1; i<10000; i++) used[i] = 0, from[i] = 0;
    q.push(start);
    used[start] = 1;
    dist[start] = 0;
    while(!q.empty()){
        int v = q.front();
        q.pop();
        if (v == finish) break;
        if (v/1000 != 9 && used[v + 1000] == 0){
            int to = v + 1000;
            used[to] = 1;
            dist[to] = dist[v] + 1;
            q.push(to);
            from[to] = v;
        }
        if (v%10 != 1 && used[v-1] == 0){
            int to = v - 1;
            used[to] = 1;
            dist[to] = dist[v] + 1;
            q.push(to);
            from[to] = v;
        }
        int v1 = v/1000;
        int v2 = (v/100) % 10;
        int v3 = (v%100) / 10;
        int v4 = v % 10; // v2, v3, v4, v1
        int to = v4 * 1000 + v1 * 100 + v2 * 10 + v3;
        if (used[to] == 0){
            used[to] = 1;
            dist[to] = dist[v] + 1;
            q.push(to);
            from[to] = v;
        }

        to = v2 * 1000 + v3 * 100 + v4 * 10 + v1;
        if (used[to] == 0){
            used[to] = 1;
            dist[to] = dist[v] + 1;
            q.push(to);
            from[to] = v;
        }
    }
    vector < int > ans;
    while(finish != 0){
        ans.push_back(finish);
        finish = from[finish];
    }
    for (int i=ans.size()-1; i>-1; i--) cout << ans[i] << '\n';
    return 0;
}
/*
Breadth First Search
*/