Submission #60956

# Submission time Handle Problem Language Result Execution time Memory
60956 2018-07-25T04:21:18 Z spencercompton Min-max tree (BOI18_minmaxtree) C++14
58 / 100
1000 ms 50536 KB
#include <bits/stdc++.h>
using namespace std;
class Edge{
public:
	int to, cap, rev;
	Edge(int a, int b, int c){
		to = a;
		cap = b;
		rev = c;
	}
};
class Flow{
public:
	int n = 140010;
	vector<Edge> adj[140010];
	int dist[140010];
	int nxt[140010];
	bool v[140010];
	int li[140010];
	Flow(){
 
	}
	void add(int i, int j){
		adj[i].push_back(Edge(j,1,adj[j].size()));
		adj[j].push_back(Edge(i,0,adj[i].size()-1));
	}
	int dfs(int now, int f){
		if(now==1){
			return f;
		}
		int did = 0;
		for(; nxt[now]<adj[now].size() && f>0; ){
			int i = nxt[now];
			int to = adj[now][i].to;
			if(adj[now][i].cap>0 && dist[to] == dist[now]+1){
				int ret = dfs(to,min(f,adj[now][i].cap));
				if(ret>0){
					adj[now][i].cap -= ret;
					adj[to][adj[now][i].rev].cap += ret;
					did += ret;
					f -= ret;
				}
			}
			if(f>0){
				nxt[now]++;
			}
			else{
				break;
			}
		}
		return did;
	}
	int bfs(){
		for(int i = 0; i<n; i++){
			dist[i] = -1;
		}
		dist[0] = 0;
		int point = 1;
		v[0] = false;
		nxt[0] = 0;
		for(int i = 0; i<point; i++){
			int now = li[i];
			for(int j = 0; j<adj[now].size(); j++){
				int to = adj[now][j].to;
				if(dist[to]==-1 && adj[now][j].cap>0){
					dist[to] = dist[now]+1;
					li[point++] = to;
					nxt[to] = 0;
					if(to==1){
						return 1;
					}
				}
			}
		}
		return 0;
	}
	int flow(){
		int ans = 0;
		while(bfs()>0){
			//do nothing
			ans += dfs(0,n);
		}
		return ans;
	}
};
int maxi[70000];
int mini[70000];
int lc[18][70000];
vector<int> adj[70000];
set<int> maxs[70000];
set<int> mins[70000];
vector<int> remmax[70000];
vector<int> remmin[70000];
int h[70000];
int dfs1(int now, int from, int x){
	lc[0][now] = from;
	h[now] = x;
	for(int i = 0; i<adj[now].size(); i++){
		int to = adj[now][i];
		if(to==from){
			continue;
		}
		dfs1(to,now,x+1);
	}
}
int mgmin(int a, int b){
	if(mins[a].size()>mins[b].size()){
		swap(a,b);
	}
	for(auto it = mins[a].begin(); it!=mins[a].end(); it++){
		mins[b].insert(*it);
	}
	mins[a].clear();
	return b;
}
int mgmax(int a, int b){
	if(maxs[a].size()>maxs[b].size()){
		swap(a,b);
	}
	for(auto it = maxs[a].begin(); it!=maxs[a].end(); it++){
		maxs[b].insert(*it);
	}
	maxs[a].clear();
	return b;
}
int lca(int a, int b){
	if(a==b){
		return a;
	}
	if(h[a] < h[b]){
		swap(a,b);
	}
	for(int i = 17; i>=0; i--){
		if(lc[i][a]!=-1 && h[lc[i][a]]>=h[b]){
			a = lc[i][a];
		}
	}
	if(a==b){
		return a;
	}
	for(int i = 17; i>=0; i--){
		int toa = lc[i][a];
		int tob = lc[i][b];
		if(toa!=tob){
			a = toa;
			b = tob;
		}
	}
	return lc[0][a];
}
pair<int, int> go(int now, int from){
	//returns minid, maxid
	pair<int, int> ret = make_pair(now,now);
	for(int i = 0; i<adj[now].size(); i++){
		int to = adj[now][i];
		if(to==from){
			continue;
		}
		pair<int, int> got = go(to,now);
		ret.first = mgmin(ret.first,got.first);
		ret.second = mgmax(ret.second,got.second);
	}
	for(int i = 0; i<remmax[now].size(); i++){
		maxs[ret.second].erase(maxs[ret.second].find(remmax[now][i]));
	}
	for(int i = 0; i<remmin[now].size(); i++){
		mins[ret.first].erase(mins[ret.first].find(remmin[now][i]));
	}
	if(maxs[ret.second].size()>0){
		maxi[now] = *maxs[ret.second].begin();
	}
	else{
		maxi[now] = -1;
	}
	if(mins[ret.first].size()>0){
		mini[now] = *mins[ret.first].rbegin();
	}
	else{
		mini[now] = -1;
	}
	return ret;
}
int main(){
	// cout << "MAIN " << endl;
	// Flow f = Flow();
	// cout << "X " << endl;
	// f.add(0,1);
	// f.add(0,4);
	// f.add(0,69);
	// f.add(69,42);
	// f.add(42,13);
	// f.add(42,1);
	// cout << "Y " << endl;
	// cout << f.flow() << endl;
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int n;
	cin >> n;
	for(int i = 1; i<n; i++){
		int a, b;
		cin >> a >> b;
		a--;
		b--;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	dfs1(0,-1,0);
	for(int i = 1; i<18; i++){
		for(int j = 0; j<n; j++){
			if(lc[i-1][j]==-1){
				lc[i][j] = -1;
			}
			else{
				lc[i][j] = lc[i-1][lc[i-1][j]];
			}
		}
	}
	int q;
	cin >> q;
	for(int i = 0; i<q; i++){
		string s;
		int a, b, v;
		cin >> s >> a >> b >> v;
		a--;
		b--;
		int l = lca(a,b);
		if(s=="M"){
			//maxi
			maxs[a].insert(v);
			maxs[b].insert(v);
			remmax[l].push_back(v);
		}
		else{
			mins[a].insert(v);
			mins[b].insert(v);
			remmin[l].push_back(v);
		}
	}
	go(0,-1);
	map<int, int> m;
	map<int, int> rev;
	int point = 2+n;
	Flow f = Flow();
	for(int i = 1; i<n; i++){
		if(mini[i]!=-1 && m.find(mini[i])==m.end()){
			rev[point] = mini[i];
			f.add(point,1);
			m[mini[i]] = point++;
		}
		if(maxi[i]!=-1 && m.find(maxi[i])==m.end()){
			rev[point] = maxi[i];
			f.add(point,1);
			m[maxi[i]] = point++;
		}
	}
	for(int i = 1; i<n; i++){
		f.add(0,2+i);
		if(mini[i]!=-1){
			f.add(2+i,m[mini[i]]);
		}
		if(maxi[i]!=-1){
			f.add(2+i,m[maxi[i]]);
		}
	}
	f.flow();
	for(int i = 1; i<n; i++){
		int found = -1;
		for(int j = 0; j<f.adj[2+i].size(); j++){
			int to = f.adj[2+i][j].to;
			if(to!=0 && f.adj[2+i][j].cap==0){
				found = rev[to];
			}
		}
		
		if(found!=-1){
			cout << (i+1) << " " << (lc[0][i]+1) << " " << found << "\n";
		}
		else if(maxi[i]!=-1){
			cout << (i+1) << " " << (lc[0][i]+1) << " " << maxi[i] << "\n";
		}
		else if(mini[i]!=-1){
			cout << (i+1) << " " << (lc[0][i]+1) << " " << mini[i] << "\n";
		}
		else{
			cout << (i+1) << " " << (lc[0][i]+1) << " " << 69 << "\n";
		}
	}
}

Compilation message

minmaxtree.cpp: In member function 'int Flow::dfs(int, int)':
minmaxtree.cpp:32:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(; nxt[now]<adj[now].size() && f>0; ){
         ~~~~~~~~^~~~~~~~~~~~~~~~
minmaxtree.cpp: In member function 'int Flow::bfs()':
minmaxtree.cpp:63:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j = 0; j<adj[now].size(); j++){
                   ~^~~~~~~~~~~~~~~~
minmaxtree.cpp: In function 'int dfs1(int, int, int)':
minmaxtree.cpp:98:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<adj[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~
minmaxtree.cpp:105:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
minmaxtree.cpp: In function 'std::pair<int, int> go(int, int)':
minmaxtree.cpp:154:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<adj[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~
minmaxtree.cpp:163:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<remmax[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~~~~
minmaxtree.cpp:166:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<remmin[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~~~~
minmaxtree.cpp: In function 'int main()':
minmaxtree.cpp:268:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j<f.adj[2+i].size(); j++){
                  ~^~~~~~~~~~~~~~~~~~
# Verdict Execution time Memory Grader output
1 Correct 20 ms 15864 KB Output is correct
2 Correct 20 ms 15864 KB Output is correct
3 Correct 23 ms 15924 KB Output is correct
4 Correct 19 ms 15948 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 838 ms 45536 KB Output is correct
2 Correct 618 ms 45536 KB Output is correct
3 Correct 849 ms 45536 KB Output is correct
4 Correct 756 ms 47044 KB Output is correct
5 Correct 670 ms 47044 KB Output is correct
6 Correct 676 ms 47044 KB Output is correct
7 Correct 582 ms 47044 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 347 ms 47044 KB Output is correct
2 Correct 412 ms 47044 KB Output is correct
3 Correct 329 ms 47044 KB Output is correct
4 Correct 349 ms 47044 KB Output is correct
5 Correct 493 ms 47044 KB Output is correct
6 Correct 561 ms 47044 KB Output is correct
7 Correct 424 ms 47044 KB Output is correct
8 Correct 559 ms 47044 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 20 ms 15864 KB Output is correct
2 Correct 20 ms 15864 KB Output is correct
3 Correct 23 ms 15924 KB Output is correct
4 Correct 19 ms 15948 KB Output is correct
5 Correct 838 ms 45536 KB Output is correct
6 Correct 618 ms 45536 KB Output is correct
7 Correct 849 ms 45536 KB Output is correct
8 Correct 756 ms 47044 KB Output is correct
9 Correct 670 ms 47044 KB Output is correct
10 Correct 676 ms 47044 KB Output is correct
11 Correct 582 ms 47044 KB Output is correct
12 Correct 347 ms 47044 KB Output is correct
13 Correct 412 ms 47044 KB Output is correct
14 Correct 329 ms 47044 KB Output is correct
15 Correct 349 ms 47044 KB Output is correct
16 Correct 493 ms 47044 KB Output is correct
17 Correct 561 ms 47044 KB Output is correct
18 Correct 424 ms 47044 KB Output is correct
19 Correct 559 ms 47044 KB Output is correct
20 Correct 783 ms 47044 KB Output is correct
21 Correct 729 ms 47044 KB Output is correct
22 Correct 631 ms 47044 KB Output is correct
23 Correct 713 ms 47044 KB Output is correct
24 Execution timed out 1084 ms 50536 KB Time limit exceeded
25 Halted 0 ms 0 KB -