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Submission #630639

# Submission time Handle Problem Language Result Execution time Memory
630639 2022-08-16T17:56:40 Z errorgorn Thousands Islands (IOI22_islands) C++17
100 / 100
 134 ms 30472 KB 
#include "islands.h"
 
#include <bits/stdc++.h>
using namespace std;
 
#define int long long
#define ii pair<int,int>
#define fi first
#define se second
 
#define puf push_front
#define pof pop_front
#define pub push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound
 
#define rep(x,s,e) for (int x=(s)-((s)>(e));x!=(e)-((s)>(e));((s)<(e))?x++:x--)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()
 
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
 
int n,m;
vector<ii> al[200005];
ii edges[200005];
bool down[200005];
 
bool vis[200005];
bool onstk[200005];
int in[200005];
ii mx[200005];
int pp[200005];
int CTIME=1;
 
void dfs(int i){
	vis[i]=true;
	onstk[i]=true;
	in[i]=CTIME++;
	mx[i]=ii(-1,-1);
 
	for (auto [it,id]:al[i]){
		if (!vis[it]){
			pp[it]=id;
			dfs(it);
			down[id]=true;
		}
 
		if (onstk[it]){
			mx[i]=max(mx[i],{in[it],id});
		}
		else{
			mx[i]=max(mx[i],mx[it]);
			down[id]=true;
		}
	}
 
	onstk[i]=false;
}
;
bool get(int i,vector<int> &v){
	vis[i]=true;
	onstk[i]=true;
 
	for (auto [it,id]:al[i]){
		if (!vis[it]){
			if (get(it,v)){
				v.pub(id);
				return true;
			}
		}
		if (onstk[it]){
			v.pub(id);
			return true;
		}
	}
 
	onstk[i]=false;
	return false;
}
 
variant<bool, vector<signed>> find_journey(
  signed N, signed M, vector<signed> U, vector<signed> V) {
 
	n=N,m=M;
 
	rep(x,0,m){
		al[U[x]].pub({V[x],x});
		edges[x]={U[x],V[x]};
	}
 
	dfs(0);
 
	//rep(x,0,n) cout<<in[x]<<" "; cout<<endl;
	//rep(x,0,n) cout<<mx[x]<<" "; cout<<endl;
 
	//rep(x,0,n) cout<<pp[x]<<" "; cout<<endl;
 
	rep(x,0,n) if (vis[x]){
		vector<ii> v;
		for (auto [it,id]:al[x]) if (down[id] && mx[it].fi>=in[x]) v.pub({it,id});
 
		if (sz(v)>=2){
			vector<int> head;
			int curr=x;
			while (curr){
				head.pub(pp[curr]);
				curr=edges[pp[curr]].fi;
			}
 
			vector<signed> ans;
			rep(x,sz(head),0) ans.pub(head[x]);
 
			while (sz(v)>2) v.pob();
 
			vector<int> tail[2],cyc[2];
			rep(y,0,2){
				memset(vis,false,sizeof(vis));
				memset(onstk,false,sizeof(onstk));
				onstk[x]=true;
				for (auto it:head) vis[edges[it].fi]=true;
				vis[x]=true;
 
				vector<int> idx;
				get(v[y].fi,idx);
				idx.pub(v[y].se);
 
				reverse(all(idx));
 
 
				vector<int> idx1,idx2;
				bool f=true;
				for (auto it:idx){
					if (edges[it].fi==edges[idx.back()].se) f=false;
					if (f) tail[y].pub(it);
					else cyc[y].pub(it);
				}
 
				//cout<<"debug: "<<v[y].fi<<endl;
				//for (auto it:tail[y]) cout<<it<<" "; cout<<endl;
				//for (auto it:cyc[y]) cout<<it<<" "; cout<<endl;
			}
 
			set<int> s;
			rep(x,0,2) for (auto it:cyc[x]) s.insert(it);
 
			if (sz(s)==sz(cyc[0])+sz(cyc[1])){
				rep(x,0,4){
					rep(y,0,sz(tail[x%2])) ans.pub(tail[x%2][y]);
					if (x/2==0){
						rep(y,0,sz(cyc[x%2])) ans.pub(cyc[x%2][y]);
					}
					else{
						rep(y,sz(cyc[x%2]),0) ans.pub(cyc[x%2][y]);
					}
					rep(y,sz(tail[x%2]),0) ans.pub(tail[x%2][y]);
				}
			}
			else{
				s.clear();
				for (auto it:cyc[0]) s.insert(it);
 
				vector<int> tail2[2];
 
				rep(x,0,2){
					vector<int> temp;
					for (auto it:tail[x]) temp.pub(it);
					for (auto it:cyc[x]) temp.pub(it);
					for (auto it:temp){
						tail2[x].pub(it);
						if (s.count(it)) break;
					}
				}
 
				//cout<<"testing: "<<endl;
				//for (auto it:tail2[0]) cout<<it<<" "; cout<<endl;
				//for (auto it:tail2[1]) cout<<it<<" "; cout<<endl;
				//for (auto it:cyc[0]) cout<<it<<" "; cout<<endl;
 
				rep(x,0,sz(tail2[0])-1) ans.pub(tail2[0][x]);
				rep(i,0,sz(cyc[0])) if (cyc[0][i]==tail2[0].back()){
					rep(x,i,sz(cyc[0])) ans.pub(cyc[0][x]);
					rep(x,0,i) ans.pub(cyc[0][x]);
				}
				rep(x,sz(tail2[0])-1,0) ans.pub(tail2[0][x]);
 
				rep(x,0,sz(tail2[1])-1) ans.pub(tail2[1][x]);
				rep(i,0,sz(cyc[0])) if (cyc[0][i]==tail2[1].back()){
					rep(x,i,0) ans.pub(cyc[0][x]);
					rep(x,sz(cyc[0]),i) ans.pub(cyc[0][x]);
				}
				rep(x,sz(tail2[1])-1,0) ans.pub(tail2[1][x]);
			}
 
			rep(x,0,sz(head)) ans.pub(head[x]);
 
			return ans;
		}
	}
 
	return false;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 5332 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 4 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 5332 KB Output is correct
7 Correct 43 ms 17696 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 5332 KB Output is correct
2 Correct 3 ms 5048 KB Output is correct
3 Correct 3 ms 5332 KB Output is correct
4 Correct 3 ms 5332 KB Output is correct
5 Correct 3 ms 5332 KB Output is correct
6 Correct 38 ms 14560 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5716 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5076 KB Output is correct
4 Correct 4 ms 5332 KB Output is correct
5 Correct 3 ms 5204 KB Output is correct
6 Correct 3 ms 5332 KB Output is correct
7 Correct 3 ms 5076 KB Output is correct
8 Correct 3 ms 5460 KB Output is correct
9 Correct 4 ms 5460 KB Output is correct
10 Correct 4 ms 5716 KB Output is correct
11 Correct 3 ms 5332 KB Output is correct
12 Correct 4 ms 5716 KB Output is correct
13 Correct 3 ms 4948 KB Output is correct
14 Correct 3 ms 4948 KB Output is correct
15 Correct 3 ms 5460 KB Output is correct
16 Correct 3 ms 4948 KB Output is correct
17 Correct 25 ms 10936 KB Output is correct
18 Correct 20 ms 10392 KB Output is correct
19 Correct 3 ms 4948 KB Output is correct
20 Correct 3 ms 5332 KB Output is correct
21 Correct 3 ms 5332 KB Output is correct
22 Correct 3 ms 5332 KB Output is correct
23 Correct 39 ms 14200 KB Output is correct

Subtask #4
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 5332 KB Output is correct
2 Correct 4 ms 5552 KB Output is correct
3 Correct 40 ms 14876 KB Output is correct
4 Correct 36 ms 15436 KB Output is correct
5 Correct 3 ms 5588 KB Output is correct
6 Correct 5 ms 5588 KB Output is correct
7 Correct 4 ms 5332 KB Output is correct
8 Correct 3 ms 5332 KB Output is correct
9 Correct 4 ms 5416 KB Output is correct
10 Correct 4 ms 5648 KB Output is correct
11 Correct 3 ms 5332 KB Output is correct
12 Correct 4 ms 5588 KB Output is correct
13 Correct 4 ms 5844 KB Output is correct
14 Correct 4 ms 5588 KB Output is correct
15 Correct 4 ms 5716 KB Output is correct
16 Correct 3 ms 5588 KB Output is correct
17 Correct 3 ms 4948 KB Output is correct
18 Correct 4 ms 5588 KB Output is correct
19 Correct 3 ms 5460 KB Output is correct
20 Correct 38 ms 15668 KB Output is correct
21 Correct 37 ms 15268 KB Output is correct
22 Correct 3 ms 5204 KB Output is correct
23 Correct 3 ms 5076 KB Output is correct
24 Correct 3 ms 4964 KB Output is correct
25 Correct 3 ms 5460 KB Output is correct
26 Correct 4 ms 5716 KB Output is correct
27 Correct 53 ms 16356 KB Output is correct
28 Correct 40 ms 16364 KB Output is correct
29 Correct 2 ms 4948 KB Output is correct
30 Correct 42 ms 16764 KB Output is correct
31 Correct 3 ms 5332 KB Output is correct
32 Correct 41 ms 16076 KB Output is correct
33 Correct 46 ms 15444 KB Output is correct
34 Correct 22 ms 10964 KB Output is correct
35 Correct 3 ms 5588 KB Output is correct
36 Correct 33 ms 14472 KB Output is correct
37 Correct 44 ms 16604 KB Output is correct
38 Correct 3 ms 5076 KB Output is correct
39 Correct 33 ms 13920 KB Output is correct
40 Correct 3 ms 5588 KB Output is correct
41 Correct 43 ms 16696 KB Output is correct
42 Correct 40 ms 16496 KB Output is correct
43 Correct 3 ms 4948 KB Output is correct
44 Correct 4 ms 5204 KB Output is correct
45 Correct 4 ms 5756 KB Output is correct
46 Correct 23 ms 10220 KB Output is correct

Subtask #5
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 5332 KB Output is correct
3 Correct 3 ms 4948 KB Output is correct
4 Correct 4 ms 4948 KB Output is correct
5 Correct 3 ms 4948 KB Output is correct
6 Correct 3 ms 5332 KB Output is correct
7 Correct 43 ms 17696 KB Output is correct
8 Correct 3 ms 5332 KB Output is correct
9 Correct 3 ms 5048 KB Output is correct
10 Correct 3 ms 5332 KB Output is correct
11 Correct 3 ms 5332 KB Output is correct
12 Correct 3 ms 5332 KB Output is correct
13 Correct 38 ms 14560 KB Output is correct
14 Correct 4 ms 5716 KB Output is correct
15 Correct 3 ms 4948 KB Output is correct
16 Correct 3 ms 5076 KB Output is correct
17 Correct 4 ms 5332 KB Output is correct
18 Correct 3 ms 5204 KB Output is correct
19 Correct 3 ms 5332 KB Output is correct
20 Correct 3 ms 5076 KB Output is correct
21 Correct 3 ms 5460 KB Output is correct
22 Correct 4 ms 5460 KB Output is correct
23 Correct 4 ms 5716 KB Output is correct
24 Correct 3 ms 5332 KB Output is correct
25 Correct 4 ms 5716 KB Output is correct
26 Correct 3 ms 4948 KB Output is correct
27 Correct 3 ms 4948 KB Output is correct
28 Correct 3 ms 5460 KB Output is correct
29 Correct 3 ms 4948 KB Output is correct
30 Correct 25 ms 10936 KB Output is correct
31 Correct 20 ms 10392 KB Output is correct
32 Correct 3 ms 4948 KB Output is correct
33 Correct 3 ms 5332 KB Output is correct
34 Correct 3 ms 5332 KB Output is correct
35 Correct 3 ms 5332 KB Output is correct
36 Correct 39 ms 14200 KB Output is correct
37 Correct 3 ms 5332 KB Output is correct
38 Correct 2 ms 4948 KB Output is correct
39 Correct 4 ms 5048 KB Output is correct
40 Correct 3 ms 5076 KB Output is correct
41 Correct 19 ms 9820 KB Output is correct
42 Correct 4 ms 5360 KB Output is correct
43 Correct 34 ms 17088 KB Output is correct
44 Correct 45 ms 15008 KB Output is correct
45 Correct 34 ms 17432 KB Output is correct
46 Correct 3 ms 5332 KB Output is correct
47 Correct 3 ms 5332 KB Output is correct
48 Correct 3 ms 5332 KB Output is correct
49 Correct 4 ms 5588 KB Output is correct
50 Correct 134 ms 30472 KB Output is correct
51 Correct 74 ms 26428 KB Output is correct
52 Correct 79 ms 27552 KB Output is correct
53 Correct 72 ms 29484 KB Output is correct
54 Correct 80 ms 25276 KB Output is correct
55 Correct 80 ms 26796 KB Output is correct
56 Correct 81 ms 26144 KB Output is correct
57 Correct 54 ms 19000 KB Output is correct
58 Correct 103 ms 23500 KB Output is correct
59 Correct 104 ms 19756 KB Output is correct
60 Correct 63 ms 20156 KB Output is correct
61 Correct 66 ms 17072 KB Output is correct
62 Correct 15 ms 7048 KB Output is correct
63 Correct 72 ms 15836 KB Output is correct
64 Correct 25 ms 11432 KB Output is correct
65 Correct 3 ms 5332 KB Output is correct
66 Correct 3 ms 5460 KB Output is correct
67 Correct 79 ms 23036 KB Output is correct
68 Correct 54 ms 16700 KB Output is correct
69 Correct 42 ms 17540 KB Output is correct
70 Correct 4 ms 5716 KB Output is correct
71 Correct 65 ms 15336 KB Output is correct
72 Correct 4 ms 5332 KB Output is correct
73 Correct 76 ms 18864 KB Output is correct
74 Correct 131 ms 28224 KB Output is correct
75 Correct 7 ms 6100 KB Output is correct
76 Correct 40 ms 15452 KB Output is correct
77 Correct 58 ms 25676 KB Output is correct
78 Correct 69 ms 20268 KB Output is correct
79 Correct 3 ms 5332 KB Output is correct
80 Correct 129 ms 27616 KB Output is correct
81 Correct 3 ms 5588 KB Output is correct
82 Correct 40 ms 15376 KB Output is correct
83 Correct 3 ms 5460 KB Output is correct
84 Correct 3 ms 5332 KB Output is correct
85 Correct 52 ms 15380 KB Output is correct
86 Correct 3 ms 5588 KB Output is correct
87 Correct 3 ms 5076 KB Output is correct
88 Correct 4 ms 5716 KB Output is correct
89 Correct 80 ms 20172 KB Output is correct
90 Correct 64 ms 17072 KB Output is correct
91 Correct 129 ms 27896 KB Output is correct
92 Correct 3 ms 5332 KB Output is correct