#include<bits/stdc++.h>
#include"grader.h"
using namespace std;
const int maxn = 260;
int MAGIC = 12;
mt19937 rng(69420);
int n = 260;
vector<int> crr;
int cnt[maxn][maxn];
int pp[maxn][maxn];
int dead[maxn][maxn];
vector<int> possible[maxn];
vector<vector<int>> amon;
vector<int> perm;
int id[maxn];
bool cmp(int a, int b){
return possible[a].size() < possible[b].size();
}
void backtrack(int x) {
if(pos == n+1){
amon.push_back(crr);
return;
}
int pos = id[x];
for(int i: possible[pos]){
if(crr[i]){
continue;
}
bool chk = 1;
for(int j = 0; j < MAGIC; j++){
int tmp = pp[j][pos] - i;
if(tmp < 0)tmp += n;
if(!cnt[j][tmp]){
chk = 0;
break;
}
}
if(!chk)continue;
for(int j = 0; j < MAGIC; j++){
int tmp = pp[j][pos] - i;
if(tmp < 0)tmp += n;
cnt[j][tmp]--;
}
crr[i] = pos;
backtrack(x+1);
crr[i] = 0;
for(int j = 0; j < MAGIC; j++){
int tmp = pp[j][pos] - i;
if(tmp < 0)tmp += n;
cnt[j][tmp]++;
}
}
}
// int query(vector<int> Q){
// int cnt = 0;
// for(int i = 0; i < n; i++){
// if(Q[i] == perm[i])cnt++;
// }
// // cout << cnt << endl;
// return cnt;
// }
void solve(int N){
n = N;
if(n <= 50)MAGIC = 7;
else MAGIC = 11;
crr.assign(n, 0);
for(int i = 1; i <= n; i++)perm.push_back(i);
shuffle(perm.begin(), perm.end(), rng);
vector<int> rd = perm;
for(int i = 0; i < MAGIC; i++){
shuffle(rd.begin(), rd.end(), rng);
for(int j = 0; j < n; j++)pp[i][rd[j]] = j;
for(int j = 0; j < n; j++){
cnt[i][j] = query(rd);
if(cnt[i][j] == n)return;
if(cnt[i][j] == 0){
for(int k = 0; k < n; k++)dead[rd[j]][j] = 1;
}
rd.push_back(rd[0]);
rd.erase(rd.begin());
}
}
for(int i = 1; i <= n; i++){
id[i] = i;
for(int j = 0; j < n; j++)if(!dead[i][j])possible[i].push_back(j);
// cout << possible[i].size() << endl;
}
sort(id+1, id+n+1, cmp);
// return;
backtrack(1);
// cout << amon.size();
query(amon[0]);
}
Compilation message
mouse.cpp: In function 'void backtrack(int)':
mouse.cpp:28:8: error: 'pos' was not declared in this scope; did you mean 'pow'?
28 | if(pos == n+1){
| ^~~
| pow
