BOJ 9019: DSLR

작성일

https://www.acmicpc.net/problem/9019

  • 3월동안 210문제 풀기 (14/210)
  • 무난한 BFS, 풀고 직접 돌려보니 숫자를 기가막히게 찾아감
  • 2를 220으로 만들려면 2->4->8->16->6001->2002->22->220
  • 아주 재미났음
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
#include <bits/stdc++.h>
using namespace std;

struct Node {
  int v, par;
  char cmd;
};

string bfs(int s, int e) {
  vector<Node> qq(20000);
  int rp = 0, wp = 0;
  vector<int> visit(10000);

  auto push = [&](Node n) { qq[wp++] = n; };
  auto pop = [&]() { return qq[rp++]; };
  push({s, -1, 0});

  while(rp != wp) {
    Node cur = pop();
    int v = cur.v;
    if(v == e) {
      push(cur);
      break;
    }

    int db = v * 2 % 10000;
    if(!visit[db]) push({db, rp-1, 'D'}), visit[db] = 1;

    int dec = (10000+v-1)% 10000;
    if(!visit[dec]) push({dec, rp-1, 'S'}), visit[dec] = 1;

    int ls = v*10%10000 + v*10/10000;
    if(!visit[ls]) push({ls, rp-1, 'L'}), visit[ls] = 1;

    int rs = v/10 + (v%10)*1000;
    if(!visit[rs]) push({rs, rp-1, 'R'}), visit[rs] = 1;
  }

  Node& cur = qq[wp-1];
  string ans;
  while(cur.v != s) {
    ans += cur.cmd;
    cur = qq[cur.par];
  }
  reverse(ans.begin(), ans.end());
  return ans;
}

int main() {
  ios::sync_with_stdio(false);
  int TC, a, b;
  cin >> TC;
  while(TC--) {
    cin >> a >> b;
    cout << bfs(a,b) << '\n';
  }
}