oj.uz

답안 #205086

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
205086 2020-02-27T20:59:44 Z BorisBarca Lampice (COCI19_lampice) C++14
73 / 110
 5000 ms 10232 KB 
/*
$$$$$$$\                      $$\           $$$$$$$\
$$  __$$\                     \__|          $$  __$$\
$$ |  $$ | $$$$$$\   $$$$$$\  $$\  $$$$$$$\ $$ |  $$ | $$$$$$\   $$$$$$\   $$$$$$$\ $$$$$$\
$$$$$$$\ |$$  __$$\ $$  __$$\ $$ |$$  _____|$$$$$$$\ | \____$$\ $$  __$$\ $$  _____|\____$$\
$$  __$$\ $$ /  $$ |$$ |  \__|$$ |\$$$$$$\  $$  __$$\  $$$$$$$ |$$ |  \__|$$ /      $$$$$$$ |
$$ |  $$ |$$ |  $$ |$$ |      $$ | \____$$\ $$ |  $$ |$$  __$$ |$$ |      $$ |     $$  __$$ |
$$$$$$$  |\$$$$$$  |$$ |      $$ |$$$$$$$  |$$$$$$$  |\$$$$$$$ |$$ |      \$$$$$$$\\$$$$$$$ |
\_______/  \______/ \__|      \__|\_______/ \_______/  \_______|\__|       \_______|\_______|
*/
#include <bits/stdc++.h>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
 
using namespace std;
 
#define PB push_back
#define MP make_pair
#define INS insert
#define LB lower_bound
#define UB upper_bound
#define pii pair <int,int>
#define pll pair <long long, long long>
#define si pair<string, int>
#define is pair<int, string>
#define X first
#define Y second
#define _ << " " <<
#define sz(x) (int)x.size()
#define all(a) (a).begin(),(a).end()
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORD(i, a, b) for (int i = (a); i > (b); --i)
#define FORR(i, l, r) for (int i = (l); i <= (r); ++i)
#define FORP(i, a, b) for ((i) = (a); (i) < (b); ++i)
#define FORA(i, x) for (auto &i : x)
#define REP(i, n) FOR(i, 0, n)
#define BITS(x) __builtin_popcount(x)
#define MSET memset
#define MCPY memcpy
#define SQ(a) (a) * (a)
#define TRACE(x) cout << #x " = " << (x) << '\n';
#define YES cout << "YES\n"
#define NO cout << "NO\n"
 
typedef long long ll;
typedef long double ld;
typedef vector <int> vi;
typedef vector <pii> vpi;
typedef vector <ll> vll;
typedef vector <pll> vpl;
typedef vector <double> vd;
typedef vector <ld> vld;
typedef vector<si> vsi;
typedef vector<is> vis;
typedef vector<string> vs;
//((float) t)/CLOCKS_PER_SEC
 
const int MOD = 1e9 + 7;
const double PI = acos(-1);
const int INF = 1e9 + 10;
const ll INFL = 1e18 + 10;
const int ABC = 30;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int dox[] = {-1, 1, 0, 0, -1, -1, 1, 1};
const int doy[] = {0, 0, -1, 1, -1, 1, -1, 1};
 
inline int sum(int a, int b){
	if (a + b < 0)
		return (a + b + MOD) % MOD;
	return (a + b) % MOD;
}
 
inline void add(int &a, int b){
	a = sum(a, b);
}
 
inline int mul(int a, int b){
	return (ll)a * (ll)b % MOD;
}
 
inline int sub(int a, int b){
	return (a - b + MOD) % MOD;
}
 
inline int fast_pot(ll pot, int n){
	ll ret = 1;
	while (n){
		if (n & 1)
			ret = (ret * pot) % MOD;
			pot = (pot * pot) % MOD;
			n >>= 1;
		}
	return ret;
}
 
inline int divide(int a, int b){
	return mul(a, fast_pot(b, MOD - 2));
}
 
ll lcm(ll a, ll b){
	return abs(a * b) / __gcd(a, b);
}
 
inline double ccw(pii A, pii B, pii C){
	return (A.X * B.Y) - (A.Y * B.X) + (B.X * C.Y) - (B.Y * C.X) + (C.X * A.Y) - (C.Y * A.X);
}
 
inline int CCW(pii A, pii B, pii C){
	double val = ccw(A, B, C);
	double eps = max(max(abs(A.X), abs(A.Y)), max(max(abs(B.X), abs(B.Y)), max(abs(C.X), abs(C.Y)))) / 1e9;
	if (val <= -eps)
		return -1;
	if (val >= eps)
		return 1;
	return 0;
}
 
void to_upper(string &x){
	REP(i, sz(x))
		x[i] = toupper(x[i]);
}
 
void to_lower(string &x){
	REP(i, sz(x))
		x[i] = tolower(x[i]);
}
 
string its(ll x){
	if (x == 0)
		return "0";
	string ret = "";
	while (x > 0){
		ret += (x % 10) + '0';
		x /= 10;
	}
	reverse(all(ret));
	return ret;
}
 
ll sti(string s){
	ll ret = 0;
	REP(i, sz(s)){
		ret *= 10;
		ret += (s[i] - '0');
	}
	return ret;
}
 
const int N = 5e4 + 10;
const int P = 31;
 
int n, up[N], down[N], pot[N], sz[N], centroid, anc[N], cookie = 1;
char s[N];
vi e[N];
int is_centroid[N];
map <pii, int> cnt;
 
void precompute(){
	pot[0] = 1;
	FOR(i, 1, n + 1)
		pot[i] = mul(pot[i - 1], P);
}
 
void dfs(int node, int dad){
	sz[node] = 1;
	FORA(nxt, e[node]){
		if (nxt == dad || is_centroid[nxt] == cookie)
			continue;
		dfs(nxt, node);
		sz[node] += sz[nxt];
	}
}
 
void find_centroid(int node, int dad, int component_size){
	int maxi = component_size - sz[node];
	FORA(nxt, e[node]){
		if (nxt == dad || is_centroid[nxt] == cookie)
			continue;
		maxi = max(maxi, sz[nxt]);
		find_centroid(nxt, node, component_size);
	}
	if (maxi <= component_size / 2)
		centroid = node;
}
 
void calc_hash(int node, int dad, int h_down, int h_up, int dep){
	down[node] = sum(mul(h_down, P), s[node] - 'a' + 1);
	up[node] = sum(h_up, mul(pot[dep], s[node] - 'a' + 1));
 
	FORA(nxt, e[node])
		if (!(is_centroid[nxt] == cookie) && nxt != dad)
			calc_hash(nxt, node, down[node], up[node], dep + 1);
}
 
void add_hash(int node, int dad, int dep, int l){
	if (dep >= l)
		return;
	cnt[{dep, down[node]}]++;
	//cout << "ADD: " << dep _ down[node] << '\n';
	FORA(nxt, e[node])
		if (nxt != dad && !(is_centroid[nxt] == cookie))
			add_hash(nxt, node, dep + 1, l);
}
 
void remove_hash(int node, int dad, int dep, int l){
	if (dep >= l)
		return;
	cnt[{dep, down[node]}]--;
	//cout << "REMOVE: " << dep _ down[node] << '\n';
	FORA(nxt, e[node])
		if (nxt != dad && !(is_centroid[nxt] == cookie))
			remove_hash(nxt, node, dep + 1, l);
}
 
bool solve(int node, int dad, int dep, int lenght){
	anc[dep] = node;

	if (dep >= lenght)
		return 0;

	if (dep == lenght - 1){
		if (up[node] == down[node])
			return 1;
	} else {
		int dep_b = (lenght - (dep + 1));
		if (dep_b <= dep && dep_b >= 0){
			if (dep == dep_b){
				//cout << "Q1" _ node + 1 _ dep_b << '\n';
				if (cnt[{dep_b, down[node]}])
					return 1;
			} else {
				int c = anc[dep - (dep_b + 1)];
				//cout << "Q2" _ node + 1 _ c + 1 _ dep_b << '\n';
				if (down[anc[dep - (dep_b + 1) + 1]] == up[anc[dep - (dep_b + 1) + 1]]){
					int h = sub(down[node], mul(pot[dep_b + 1], down[c]));
					if (cnt[{dep_b, h}])
						return 1;
				}
			}
		}
	}
 
	bool ret = 0;
	FORA(nxt, e[node])
		if (nxt != dad && !(is_centroid[nxt] == cookie))
			ret |= solve(nxt, node, dep + 1, lenght);
	return ret;
}	
 
void optimize(){
	REP(i, n)
		is_centroid[i] = 0;
}

bool decompose(int node, int lenght){
	if (lenght == 1)
		return 1;
	dfs(node, -1);
	if (sz[node] < lenght)
		return 0;
 
	//cout << "-----------\n";
 
	find_centroid(node, -1, sz[node]);
	assert(centroid != -1);
	calc_hash(centroid, -1, 0, 0, 0);
	is_centroid[centroid] = cookie;	
 
	add_hash(centroid, -1, 0, lenght);
	bool ret = 0;
	FORA(nxt, e[centroid]){
		if (is_centroid[nxt] == cookie)
			continue;
		anc[0] = centroid;
		remove_hash(nxt, centroid, 1, lenght);
		//cout << nxt + 1 << '\n';
		ret |= solve(nxt, centroid, 1, lenght);
		add_hash(nxt, centroid, 1, lenght);
	}
	cnt.clear();
 
	FORA(nxt, e[centroid]){
		if (is_centroid[nxt] == cookie)
			continue;
		ret |= decompose(nxt, lenght);
	}
 
	return ret;
}
 
int parni(){
	int lo = 0, hi = (n + 1) / 2;
	while (lo < hi){
		int mid = (lo + hi + 1) / 2;
		//memset(is_centroid, 0, sizeof is_centroid);
		//optimize();
		if (decompose(1, 2 * mid))
			lo = mid;
		else
			hi = mid - 1;
		cookie++;
	}
	return 2 * lo;
}
 
int neparni(){
	int lo = 0, hi = (n + 1) / 2;
	while (lo < hi){
		int mid = (lo + hi + 1) / 2;
		//memset(is_centroid, 0, sizeof is_centroid);
		optimize();
		if (decompose(1, 2 * mid + 1))
			lo = mid;
		else
			hi = mid - 1;
		cookie++;
	}
	return 2 * lo + 1;
}
 
int main () {
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	
	scanf("%d%s", &n, s);
	REP(i, n - 1){
		int x, y; scanf("%d%d", &x, &y);
		x--, y--;
		e[x].PB(y);
		e[y].PB(x);
	}
 
	precompute();
	cookie = 1;
 
	printf("%d\n", max(parni(), neparni()));
 
	return 0;
}

Compilation message

lampice.cpp:13:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("O3")
 
lampice.cpp:14:0: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
 #pragma GCC optimization ("unroll-loops")
 
lampice.cpp: In function 'int fast_pot(ll, int)':
lampice.cpp:92:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   if (n & 1)
   ^~
lampice.cpp:94:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
    pot = (pot * pot) % MOD;
    ^~~
lampice.cpp: In function 'int main()':
lampice.cpp:330:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%s", &n, s);
  ~~~~~^~~~~~~~~~~~~~~
lampice.cpp:332:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int x, y; scanf("%d%d", &x, &y);
             ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 1528 KB Output is correct
2 Correct 19 ms 1532 KB Output is correct
3 Correct 53 ms 1768 KB Output is correct
4 Correct 63 ms 1656 KB Output is correct
5 Correct 5 ms 1528 KB Output is correct
6 Correct 5 ms 1528 KB Output is correct
7 Correct 5 ms 1528 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1125 ms 9084 KB Output is correct
2 Correct 960 ms 9208 KB Output is correct
3 Correct 952 ms 9392 KB Output is correct
4 Correct 1006 ms 9848 KB Output is correct
5 Correct 1104 ms 10232 KB Output is correct
6 Correct 664 ms 8700 KB Output is correct

Subtask #3
31.0 / 31.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2948 ms 8172 KB Output is correct
2 Correct 3210 ms 7880 KB Output is correct
3 Correct 3392 ms 8068 KB Output is correct
4 Correct 2186 ms 7288 KB Output is correct
5 Correct 2465 ms 7416 KB Output is correct
6 Correct 2285 ms 6904 KB Output is correct

Subtask #4
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 1528 KB Output is correct
2 Correct 19 ms 1532 KB Output is correct
3 Correct 53 ms 1768 KB Output is correct
4 Correct 63 ms 1656 KB Output is correct
5 Correct 5 ms 1528 KB Output is correct
6 Correct 5 ms 1528 KB Output is correct
7 Correct 5 ms 1528 KB Output is correct
8 Correct 1125 ms 9084 KB Output is correct
9 Correct 960 ms 9208 KB Output is correct
10 Correct 952 ms 9392 KB Output is correct
11 Correct 1006 ms 9848 KB Output is correct
12 Correct 1104 ms 10232 KB Output is correct
13 Correct 664 ms 8700 KB Output is correct
14 Correct 2948 ms 8172 KB Output is correct
15 Correct 3210 ms 7880 KB Output is correct
16 Correct 3392 ms 8068 KB Output is correct
17 Correct 2186 ms 7288 KB Output is correct
18 Correct 2465 ms 7416 KB Output is correct
19 Correct 2285 ms 6904 KB Output is correct
20 Correct 3088 ms 5376 KB Output is correct
21 Correct 3734 ms 6452 KB Output is correct
22 Execution timed out 5066 ms 6776 KB Time limit exceeded
23 Halted 0 ms 0 KB -