oj.uz

Submission #223428

# Submission time Handle Problem Language Result Execution time Memory
223428 2020-04-15T09:06:40 Z oolimry Lampice (COCI19_lampice) C++14
42 / 110
 121 ms 52856 KB 
#include <bits/stdc++.h>
 
using namespace std;
static vector<int> adj[50005];
static int low[50005];
static int high[50005];
static int depth[50005];
static int p[50005];
int cnt = 0; ///set to 1 if you're using fenwick tree
string s;
 
void dfs(int u, int P){
	low[u] = cnt;
	high[u] = cnt;
	cnt++;
	for(int v : adj[u]){
		if(v == P) continue;
		p[v] = u;
		depth[v] = depth[u] + 1;
		dfs(v, u);
		high[u] = max(high[u], high[v]);
	}
}
 
static int memo[3005][3005];
 
int dp(int u, int v){
	
	if(s[u] != s[v]) return -1;
	if(u == v) return 1;
	if(p[u] == v || p[v] == u) return 2;
	
	if(memo[u][v] != 0) return memo[u][v];
	
	if(depth[u] < depth[v]) swap(u,v);
 
	int a, b;
	if(low[v] <= low[u] && low[u] <= high[v]){
		a = p[u];
		for(int x : adj[v]){
			if(low[x] <= low[u] && low[u] <= high[x] && x != p[v]){
				b = x;
				break;
			}
		}
		
	}
	else{
		a = p[u]; b = p[v];
	}
	
	
	
	int ans = 0;
	
	ans = dp(a,b) + 2;
	if(ans <= 1) ans = -1;
	
	memo[u][v] = ans;
	return ans;
}

int edges[500005][26];
int backedge[500005];
int len[500005];

int PREV=0;
int INDEX=1;

void eertree(){
	memset(edges,-1,sizeof(edges));
	backedge[0]=0,backedge[1]=0;
	len[0]=-1,len[1]=0;

	for (int x=0;x<s.size();x++){
		while (s[x-len[PREV]-1]!=s[x]) 
			PREV=backedge[PREV];
		
		if (edges[PREV][s[x]-'a']==-1) 
			edges[PREV][s[x]-'a']=++INDEX;
		int curr=edges[PREV][s[x]-'a'];
		len[curr]=len[PREV]+2;
		
		if (len[curr]==1){
			backedge[curr]=1;
		}
		else{
			int b=backedge[PREV];
			while (s[x-len[b]-1]!=s[x]) b=backedge[b];
			backedge[curr]=edges[b][s[x]-'a'];
		}
		
		PREV=curr;
	}
	
	int ans = 0;
	for(int i = 0;i < 500000;i++){
		ans = max(ans, len[i]);
	}
	
	cout << ans;

	
}
 
int main(){
	//freopen("i.txt","r",stdin);
	ios_base::sync_with_stdio(false);
	cin.tie(0);
 
	int n; cin >> n;
	cin >> s;
	
	
	if(n > 3000){
		eertree();
		exit(0);
	}
	
	for(int i = 0;i < n-1;i++){
		int a, b; cin >> a >> b;
		a--; b--;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	
	dfs(0,-1);
	
	int ans = 0;
	for(int i = 0;i < n;i++){
		for(int j = 0;j < n;j++){
			//cout << dp(i,j) << " ";
			ans = max(ans, dp(i,j));
		}
		//cout << "\n";
	}
	cout << ans;
}

Compilation message

lampice.cpp: In function 'void eertree()':
lampice.cpp:75:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int x=0;x<s.size();x++){
               ~^~~~~~~~~
lampice.cpp: In function 'int dp(int, int)':
lampice.cpp:56:10: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  ans = dp(a,b) + 2;
        ~~^~~~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 3456 KB Output is correct
2 Correct 18 ms 7040 KB Output is correct
3 Correct 38 ms 16376 KB Output is correct
4 Correct 121 ms 27260 KB Output is correct
5 Correct 5 ms 1536 KB Output is correct
6 Correct 5 ms 1536 KB Output is correct
7 Correct 5 ms 1536 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 52588 KB Output is correct
2 Correct 34 ms 52728 KB Output is correct
3 Correct 34 ms 52856 KB Output is correct
4 Correct 34 ms 52856 KB Output is correct
5 Correct 34 ms 52736 KB Output is correct
6 Correct 34 ms 52856 KB Output is correct

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Incorrect 35 ms 52472 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 3456 KB Output is correct
2 Correct 18 ms 7040 KB Output is correct
3 Correct 38 ms 16376 KB Output is correct
4 Correct 121 ms 27260 KB Output is correct
5 Correct 5 ms 1536 KB Output is correct
6 Correct 5 ms 1536 KB Output is correct
7 Correct 5 ms 1536 KB Output is correct
8 Correct 34 ms 52588 KB Output is correct
9 Correct 34 ms 52728 KB Output is correct
10 Correct 34 ms 52856 KB Output is correct
11 Correct 34 ms 52856 KB Output is correct
12 Correct 34 ms 52736 KB Output is correct
13 Correct 34 ms 52856 KB Output is correct
14 Incorrect 35 ms 52472 KB Output isn't correct
15 Halted 0 ms 0 KB -