oj.uz

Submission #60963

# Submission time Handle Problem Language Result Execution time Memory
60963 2018-07-25T04:28:09 Z spencercompton Min-max tree (BOI18_minmaxtree) C++14
58 / 100
 1000 ms 51360 KB 
#include <bits/stdc++.h>
using namespace std;
class Edge{
public:
	int to, rev;
	bool cap;
	Edge(int a, bool b, int c){
		to = a;
		cap = b;
		rev = c;
	}
};
class Flow{
public:
	int n = 140010;
	vector<Edge> adj[140010];
	int sz[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,sz[j]++));
		adj[j].push_back(Edge(i,0,sz[i]++));
	}
	bool dfs(int now){
		if(now==1){
			return true;
		}
		for(; nxt[now]<sz[now]; ){
			int i = nxt[now];
			int to = adj[now][i].to;
			if(adj[now][i].cap && dist[to] == dist[now]+1 && dfs(to)){
				adj[now][i].cap = false;
				adj[to][adj[now][i].rev].cap = true;
				return true;
			}
			nxt[now]++;
		}
		return false;
	}
	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<sz[now]; 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
			for(int i = 0; i<sz[0]; i++){
				int to = adj[0][i].to;
				if(dist[to]==1 && adj[0][i].cap && dfs(to)){
					adj[0][i].cap = false;
					adj[to][adj[0][i].rev].cap = true;
				}
			}
		}
		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 function 'int dfs1(int, int, int)':
minmaxtree.cpp:97:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<adj[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~
minmaxtree.cpp:104:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
minmaxtree.cpp: In function 'std::pair<int, int> go(int, int)':
minmaxtree.cpp:153:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<adj[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~
minmaxtree.cpp:162:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0; i<remmax[now].size(); i++){
                 ~^~~~~~~~~~~~~~~~~~~
minmaxtree.cpp:165:18: 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:267:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j<f.adj[2+i].size(); j++){
                  ~^~~~~~~~~~~~~~~~~~

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 15864 KB Output is correct
2 Correct 17 ms 15864 KB Output is correct
3 Correct 17 ms 15920 KB Output is correct
4 Correct 16 ms 15920 KB Output is correct

Subtask #2
22.0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 809 ms 46168 KB Output is correct
2 Correct 660 ms 46168 KB Output is correct
3 Correct 744 ms 46168 KB Output is correct
4 Correct 945 ms 47492 KB Output is correct
5 Correct 795 ms 47492 KB Output is correct
6 Correct 858 ms 47492 KB Output is correct
7 Correct 666 ms 47492 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 461 ms 47492 KB Output is correct
2 Correct 432 ms 47492 KB Output is correct
3 Correct 435 ms 47492 KB Output is correct
4 Correct 374 ms 47492 KB Output is correct
5 Correct 407 ms 47492 KB Output is correct
6 Correct 577 ms 47492 KB Output is correct
7 Correct 382 ms 47492 KB Output is correct
8 Correct 417 ms 47492 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 15864 KB Output is correct
2 Correct 17 ms 15864 KB Output is correct
3 Correct 17 ms 15920 KB Output is correct
4 Correct 16 ms 15920 KB Output is correct
5 Correct 809 ms 46168 KB Output is correct
6 Correct 660 ms 46168 KB Output is correct
7 Correct 744 ms 46168 KB Output is correct
8 Correct 945 ms 47492 KB Output is correct
9 Correct 795 ms 47492 KB Output is correct
10 Correct 858 ms 47492 KB Output is correct
11 Correct 666 ms 47492 KB Output is correct
12 Correct 461 ms 47492 KB Output is correct
13 Correct 432 ms 47492 KB Output is correct
14 Correct 435 ms 47492 KB Output is correct
15 Correct 374 ms 47492 KB Output is correct
16 Correct 407 ms 47492 KB Output is correct
17 Correct 577 ms 47492 KB Output is correct
18 Correct 382 ms 47492 KB Output is correct
19 Correct 417 ms 47492 KB Output is correct
20 Correct 813 ms 47492 KB Output is correct
21 Correct 610 ms 47492 KB Output is correct
22 Correct 664 ms 47492 KB Output is correct
23 Correct 611 ms 47492 KB Output is correct
24 Execution timed out 1040 ms 51360 KB Time limit exceeded
25 Halted 0 ms 0 KB -