Submission #365513

#	Time	Username	Problem	Language	Result	Execution time	Memory
365513		kostia244	parentrises (BOI18_parentrises)	C++17	72 / 100	1084 ms	65116 KiB

parentrises

#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2")
#include<bits/stdc++.h>
#define all(x) begin(x), end(x)
using namespace std;
using ll = long long;
vector<vector<int>> g;
string solve(string s) {
	g.assign(s.size(), {});
	vector<int> z[2];
	auto check = [&](string s) {
		int ok = 1, a = 0, b = 0, c = count(all(s), '('), d = count(all(s), ')');
		for(auto i : s) {
			ok &= b <= 2*a;
			ok &= c <= 2*d;
			if(i == ')') swap(a, b), swap(c, d);
			a++, c--;
			if(i == ')') swap(a, b), swap(c, d);
			ok &= b <= 2*a;
			ok &= c <= 2*d;
		}
		return ok;
	};
	if(!check(s)) return "impossible";
	for(auto &i : s) {
		int pos = &i-&s[0];
		if(i == '(') {
			z[0].push_back(pos);
		} else {
			if(z[0].empty()) {
				if(z[1].empty()) return "wimpossible";
				g[pos].push_back(z[1].back());
				g[z[1].back()].push_back(pos);
				z[1].pop_back();
			} else {
				g[pos].push_back(z[0].back());
				g[z[0].back()].push_back(pos);
				z[1].push_back(z[0].back());
				z[0].pop_back();
			}
		}/*
		cout << pos << ": ";
		for(auto i : z[0]) cout << i << " "; cout << " | ";
		for(auto i : z[1]) cout << i << " "; cout << endl;*/
	}
	reverse(all(s));
	z[0].clear();
	for(auto &i : s) {
		int pos = &i-&s[0];
		pos = s.size()-1-pos;
		if(i == ')') {
			if(g[pos].size() < 2) z[0].push_back(pos);
		} else if(g[pos].empty()) {
			if(z[0].empty()) return "wimpossible";
			g[pos].push_back(z[0].back());
			g[z[0].back()].push_back(pos);
			z[0].pop_back();
		}
	}
	reverse(all(s));
	vector<int> col(s.size());
	for(int i = 0; i < s.size(); i++) {
		if(g[i].size() == 2) {
			int c = 1;
			for(auto v : g[i]) col[v] = c++;
		}
	}
	s = "";
	for(auto i : col) {
		if(i == 0) s += "G";
		if(i == 1) s += "B";
		if(i == 2) s += "R";
	}
	return s;
}
int F[301];
int dp[302][301];
const int mod = 1e9 + 7;
void add(int &a, int b) {
	a = a+b>=mod?a+b-mod:a+b;
}
int f(int n) {
	if(F[n] != -1) return F[n];
	F[n] = 0;
	for(int c0 = 0; c0 <= n; c0++) {
		int c1 = n-c0;
		memset(dp, 0, sizeof dp);
		dp[0][0] = 1;
		for(int i = 0; i <= n; i++) {
			for(int z = 0; z <= i; z++) {
				int o = i-z;
				dp[i][z] *= (z <= 2*o && (c1-o) <= 2*(c0-z));
				//if(dp[i][z]) cout << i << " " << z << " " << dp[i][z] << " " << F[n] << endl;
				add(dp[i+1][z], dp[i][z]);
				add(dp[i+1][z+1], dp[i][z]);
				if(i == n && z == c0) {
					add(F[n], dp[i][z]);
					//cout << i << " "<< z << " | " << c0 << " " << dp[i][z] << endl;
				}
			}
		}
	}
	return F[n];
}
void calc() {
	for(int i = 0; i < 301; i++) F[i] = -1;
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	int t, x;
	string s;
	cin >> t;
	if(t == 1) {
		cin >> t;
		while(t--) {
			cin >> s;
			cout << solve(s) << '\n';
		}
	} else {
		calc();
		cin >> t;
		while(t--) cin >> x, cout << f(x) << endl;
	}
}

Compilation message (stderr)

parentrises.cpp: In function 'std::string solve(std::string)':
parentrises.cpp:62:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |  for(int i = 0; i < s.size(); i++) {
      |                 ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 6 / 6
• Subtask 4: 28 / 28
• Subtask 5: 6 / 6
• Subtask 6: 16 / 16
• Subtask 7: 0 / 28