Submission #2123614

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Source Code Expand

#include <bits/stdc++.h>
// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <cmath>
#include <iomanip>
#include <time.h>
#include <unistd.h>
#define dibs reserve
#define OVER9000 1234567890
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define tisic 47
#define soclose 1e-8
#define chocolate win
// so much chocolate
#define patkan 9
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):x)
#define uint unsigned int
#define dbl long double
#define pi 3.14159265358979323846
using namespace std;
// mylittledoge

typedef long long cat;

#ifdef DONLINE_JUDGE
	// palindromic tree is better than splay tree!
	#define lld I64d
#endif

int ops[25000];
int cnt_ops =0;

void move(int cur, vector<int> &P, vector<int> &par) {
	assert(cnt_ops < 14000);
	ops[cnt_ops++] =cur;
	int v =cur, tmp =P[0];
	while(true) {
		swap(P[v], tmp);
		if(v == 0) break;
		v =par[v];
	}
}

int main() {
	cin.sync_with_stdio(0);
	cin.tie(0);
	cout << fixed << setprecision(10);
	int N;
	cin >> N;
	vector<int> P(N), par(N, 0), D(N, 0);
	vector< vector<int> > G(N);
	for(int i =1; i < N; i++) {
		cin >> par[i];
		G[par[i]].push_back(i);
		D[par[i]]++;
	}
	for(int i =0; i < N; i++) cin >> P[i];

	vector<bool> bl(N, false);
	while(!bl[0]) {
		vector<int> in_path(N, -1), in_path_id(N, -1);
		vector< vector< pair<int, int> > > paths;
		for(int i =N-1; i >= 0; i--) if(!bl[i] && D[i] == 0) {
			vector< pair<int, int> > path;
			int v =i;
			while(D[v] <= 1) {
				in_path[v] =paths.size();
				path.push_back(make_pair(v, -1));
				if(v == 0) break;
				v =par[v];
			}
			reverse(begin(path), end(path));
			for(int j =0; j < (int)path.size(); j++) in_path_id[path[j].ff] =j;
			paths.push_back(path);
		}

		int cur =N-1;
		while(true) {
//			for(int i =0; i < N; i++) cerr << P[i] << " "; cerr << "\n";
			int v =P[0];
			if(in_path[v] != -1) {
				int p =in_path[v], x =(int)paths[in_path[v]].size()-1;
				while(paths[p][x].ss > v) x--;
				for(int i =1; i <= x; i++) paths[p][i-1].ss =paths[p][i].ss;
				paths[p][x].ss =v;
				move(paths[p][x].ff, P, par);
			}
			while(cur >= 0) {
				if(bl[cur]) cur--;
				else if(in_path[cur] != -1 && paths[in_path[cur]][in_path_id[cur]].ss != -1) cur--;
				else break;
			}
			if(cur < 0) break;
			if(in_path[v] == -1) {
				move(cur, P, par);
				cur--;
			}
		}
//		for(int i =0; i < N; i++) cerr << P[i] << " "; cerr << ".\n";

		for(int i =0; i < N; i++) if(in_path[i] != -1) {
			bl[i] =true;
			D[par[i]]--;
		}
	}

	cout << cnt_ops << "\n";
	for(int i =0; i < cnt_ops; i++) cout << ops[i] << "\n";
	return 0;}

// look at my code
// my code is amazing

Submission Info

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