oj.uz

답안 #205078

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
205078 2020-02-27T20:48:35 Z BorisBarca Lampice (COCI19_lampice) C++14
73 / 110
 5000 ms 9972 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];
char s[N];
vi e[N];
bool 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])
			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])
			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] && 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])
			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])
			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])
			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] = 1;	
 
	add_hash(centroid, -1, 0, lenght);
	bool ret = 0;
	FORA(nxt, e[centroid]){
		if (is_centroid[nxt])
			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])
			continue;
		ret |= decompose(nxt, lenght);
	}
 
	return ret;
}
 
int parni(){
	int cnt = 0;
	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;
		cnt++;
	}
	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;
	}
	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();
 
	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 10 ms 1404 KB Output is correct
2 Correct 18 ms 1528 KB Output is correct
3 Correct 51 ms 1784 KB Output is correct
4 Correct 61 ms 1656 KB Output is correct
5 Correct 5 ms 1528 KB Output is correct
6 Correct 6 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 1115 ms 8952 KB Output is correct
2 Correct 955 ms 9080 KB Output is correct
3 Correct 850 ms 9336 KB Output is correct
4 Correct 1051 ms 9720 KB Output is correct
5 Correct 1126 ms 9972 KB Output is correct
6 Correct 650 ms 8400 KB Output is correct

Subtask #3
31.0 / 31.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2783 ms 8056 KB Output is correct
2 Correct 3801 ms 7800 KB Output is correct
3 Correct 3723 ms 7924 KB Output is correct
4 Correct 2436 ms 7100 KB Output is correct
5 Correct 2783 ms 7172 KB Output is correct
6 Correct 2409 ms 6720 KB Output is correct

Subtask #4
0 / 37.0

# 결과 실행 시간 메모리 Grader output
1 Correct 10 ms 1404 KB Output is correct
2 Correct 18 ms 1528 KB Output is correct
3 Correct 51 ms 1784 KB Output is correct
4 Correct 61 ms 1656 KB Output is correct
5 Correct 5 ms 1528 KB Output is correct
6 Correct 6 ms 1528 KB Output is correct
7 Correct 5 ms 1528 KB Output is correct
8 Correct 1115 ms 8952 KB Output is correct
9 Correct 955 ms 9080 KB Output is correct
10 Correct 850 ms 9336 KB Output is correct
11 Correct 1051 ms 9720 KB Output is correct
12 Correct 1126 ms 9972 KB Output is correct
13 Correct 650 ms 8400 KB Output is correct
14 Correct 2783 ms 8056 KB Output is correct
15 Correct 3801 ms 7800 KB Output is correct
16 Correct 3723 ms 7924 KB Output is correct
17 Correct 2436 ms 7100 KB Output is correct
18 Correct 2783 ms 7172 KB Output is correct
19 Correct 2409 ms 6720 KB Output is correct
20 Correct 3058 ms 5172 KB Output is correct
21 Correct 3949 ms 6256 KB Output is correct
22 Execution timed out 5072 ms 6648 KB Time limit exceeded
23 Halted 0 ms 0 KB -