函数的魔法

函数的魔法

裸的直接写就好了。

#include <bits/stdc++.h>

using namespace std;

const int mod = 233;

int vis[mod + 10];

typedef pair<int, int> pii;

int f(int x) {
  return (1ll * x * x % mod * x % mod + 1ll * x * x % mod) % mod;
}

int g(int x) {
  return (1ll * x * x % mod * x % mod - 1ll * x * x % mod + mod) % mod;
}

int main() {
  // freopen("in.txt", "r", stdin);
  // freopen("out.txt", "w", stdout);
  // ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  int T;
  scanf("%d", &T);
  while(T--) {
    memset(vis, 0, sizeof vis);
    queue<pii> q;
    int a, b;
    scanf("%d %d", &a, &b);
    if (a == b) {
      puts("0");
      continue;
    }
    else if (b >= mod) {
      puts("-1");
      continue;
    }
    else if (a >= mod) {
      int x = f(a), y = g(a);
      vis[x] = vis[y] = 1;
      q.push(make_pair(x, 1));
      q.push(make_pair(y, 1));
    }
    else {
      vis[a] = 1;
      q.push(make_pair(a, 0));
    }
    int ans = -1;
    while(q.size()) {
      auto it = q.front();
      q.pop();
      if (it.first == b) {
        ans = it.second;
        break;
      }
      int a = f(it.first), b = g(it.first);
      if (!vis[a]) {
        vis[a] = 1;
        q.push(make_pair(a, it.second + 1));
      }
      if (!vis[b]) {
        q.push(make_pair(b, it.second + 1));
      }
    }
    printf("%d\n", ans);
  }
  return 0;
}