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Submission #885785

# Submission time Handle Problem Language Result Execution time Memory
885785 2023-12-10T18:00:48 Z vjudge1 Lampice (COCI19_lampice) C++17
110 / 110
 1824 ms 29912 KB 
/**
 *    author:  AgentPengin ( Độc cô cầu bại )
 *    created: 23.12.2022 10:08:02
 *    too lazy to update time
**/
#include<bits/stdc++.h>

#define EL '\n'
#define fi first
#define se second
#define NAME "TASK"
#define ll long long
#define lcm(a,b) (a/gcd(a,b))*b
#define db(val) "["#val" = " << (val) << "] "
#define bend(v) (v).begin(),(v).end()
#define sz(v) (int)(v).size()
#define ex exit(0)

using namespace std;

const ll mod = 1e9 + 7;
const int inf = 0x1FFFFFFF;
const int MAXN = 2e5 + 5;
const ll base = 35711;

int n,Len,valid[MAXN],child[MAXN],mx_depth;
char a[MAXN];
vector<int> adj[MAXN];
vector<pair<int,ll>> b;
ll po[MAXN];
unordered_map<ll,bool> f[MAXN];

void countChild(int u,int p) {
	child[u] = 1;
	for (auto v : adj[u]) {
		if (v != p && valid[v]) {
			countChild(v,u);
			child[u] += child[v];
		}
	}
}

bool dfs(int u,int p,int h,ll hashdown,ll hashup) {
	if (h > Len) return false;
	if (p) {
		hashdown = (hashdown * base + a[u]) % mod;
	}
	hashup = (hashup + 1LL * a[u] * po[h - 1]) % mod;
	ll x = (hashup * po[Len - h] - hashdown + mod) % mod;
	if (!p) f[h][x] = true;
	if (f[Len - h + 1].find(x) != f[Len - h + 1].end()) return true;
	
	for (auto v : adj[u]) {
		if (v != p && valid[v]) {
			if (!p) b.clear();
			if (dfs(v,u,h + 1,hashdown,hashup)) return true;
			if (!p) {
				for (auto x : b) {
					f[x.fi][x.se] = true;
				}
			}
		}
	}
	mx_depth = max(mx_depth,h);
	b.push_back({h,x});
	return false;
}

bool solve(int u,int n) {
	countChild(u,0);
	int flag = 1,half = n / 2;
	while(flag) {
		flag = 0;
		for (auto v : adj[u]) {
			if (valid[v] && child[v] < child[u] && child[v] > half) {
				u = v;
				flag = true;
				break;
			}
		}
	}
	countChild(u,0);
	if (dfs(u,0,1,0,0)) return true;
	for (int i = 1;i <= mx_depth;i++) f[i].clear();
	mx_depth = 0;
	valid[u] = false;
	for (auto v : adj[u]) {
		if (valid[v]) {
			if (solve(v,child[v])) return true;
		}
	}
	return false;
}

bool check(int len) {
	Len = len;
	for (int i = 1;i <= n;i++) {
		valid[i] = 1;
		f[i].clear();
	} 
	return solve(1,n);
}

signed main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    if (ifstream(NAME".inp")) {
        freopen(NAME".inp","r",stdin);
        freopen(NAME".out","w",stdout);
    }
    cin >> n;
    for (int i = 1;i <= n;i++) cin >> a[i];
    for (int i = 1;i < n;i++) {
    	int u,v; cin >> u >> v;
    	adj[u].push_back(v);
    	adj[v].push_back(u);
    }
    po[0] = 1;
    for (int i = 1;i <= n;i++) po[i] = po[i - 1] * base % mod;
    int l = 0,r = (n - 1) / 2;
    while(l < r) {
    	int mid = (l + r + 1) >> 1;
    	if (check(mid * 2 + 1)) {
    		l = mid;
    	} else {
    		r = mid - 1;
    	}
    }
    int ans = r * 2 + 1;
    l = 0,r = n / 2;
    while(l < r) {
    	int mid = (l + r + 1) >> 1;
    	if (check(mid * 2)) {
    		l = mid;
    	} else r = mid - 1;
    }
    cout << max(ans,r * 2);
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}
// agent pengin wants to take apio (with anya-san)

Compilation message

lampice.cpp: In function 'int main()':
lampice.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen(NAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
lampice.cpp:108:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  108 |         freopen(NAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 19292 KB Output is correct
2 Correct 8 ms 19036 KB Output is correct
3 Correct 20 ms 19036 KB Output is correct
4 Correct 25 ms 19036 KB Output is correct
5 Correct 4 ms 19036 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19036 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 817 ms 28452 KB Output is correct
2 Correct 821 ms 28660 KB Output is correct
3 Correct 589 ms 29084 KB Output is correct
4 Correct 679 ms 29408 KB Output is correct
5 Correct 1036 ms 29912 KB Output is correct
6 Correct 121 ms 29108 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1662 ms 25300 KB Output is correct
2 Correct 1824 ms 24568 KB Output is correct
3 Correct 1645 ms 25492 KB Output is correct
4 Correct 1513 ms 25296 KB Output is correct
5 Correct 1200 ms 24272 KB Output is correct
6 Correct 1200 ms 23896 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 19292 KB Output is correct
2 Correct 8 ms 19036 KB Output is correct
3 Correct 20 ms 19036 KB Output is correct
4 Correct 25 ms 19036 KB Output is correct
5 Correct 4 ms 19036 KB Output is correct
6 Correct 4 ms 19036 KB Output is correct
7 Correct 4 ms 19036 KB Output is correct
8 Correct 817 ms 28452 KB Output is correct
9 Correct 821 ms 28660 KB Output is correct
10 Correct 589 ms 29084 KB Output is correct
11 Correct 679 ms 29408 KB Output is correct
12 Correct 1036 ms 29912 KB Output is correct
13 Correct 121 ms 29108 KB Output is correct
14 Correct 1662 ms 25300 KB Output is correct
15 Correct 1824 ms 24568 KB Output is correct
16 Correct 1645 ms 25492 KB Output is correct
17 Correct 1513 ms 25296 KB Output is correct
18 Correct 1200 ms 24272 KB Output is correct
19 Correct 1200 ms 23896 KB Output is correct
20 Correct 912 ms 22276 KB Output is correct
21 Correct 1051 ms 23240 KB Output is correct
22 Correct 1457 ms 23580 KB Output is correct
23 Correct 387 ms 21720 KB Output is correct
24 Correct 1279 ms 23732 KB Output is correct
25 Correct 1324 ms 22984 KB Output is correct
26 Correct 1566 ms 25412 KB Output is correct
27 Correct 1722 ms 24108 KB Output is correct
28 Correct 1022 ms 21976 KB Output is correct
29 Correct 1093 ms 22004 KB Output is correct
30 Correct 1208 ms 24696 KB Output is correct
31 Correct 1077 ms 23008 KB Output is correct
32 Correct 1020 ms 25716 KB Output is correct
33 Correct 773 ms 23384 KB Output is correct