Submission #861862

#	Time	Username	Problem	Language	Result	Execution time	Memory
861862		iskhakkutbilim	parentrises (BOI18_parentrises)	C++17	16 / 100	131 ms	262144 KiB

parentrises

#include <bits/stdc++.h>
using namespace std;

#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int mod = 1e9 + 7;

int P;

void solve(){
	string s; cin >> s;
	int n = s.size();
	map<pair<int, int>, bool> dp[n];
	string path[n][n + 1][n + 1];	
	// RBG
	if(s[0] == ')' or s[n-1] == '('){
		cout << "impossible";
		return;
	}
	dp[0][{0, 1}] = 1, dp[0][{1, 0}] = 1;
	dp[0][{1, 1}] = 1;
	path[0][0][1] = "R";
	path[0][1][1] = "G";
	path[0][1][0] = "B";
	vector<int> pref(n);
	pref[0] = 1;
	for(int i = 1;i < n; i++){
		pref[i] = pref[i-1] + s[i]==')' ? -1 : 1;
	}
	for(int i = 1;i < n; i++){
		for(auto [pp, y] : dp[i-1]){
			int x1 = pp.ff, x2 = pp.ss;
			int ok = 0;
			int c = s[i]==')' ? -1 : 1;
			if(x2 + c >= 0){
				ok++;
				dp[i][{x1, x2 + c}] = 1;
				path[i][x1][x2 + c] = path[i-1][x1][x2] + "R";
			}
			if(x1 + c >= 0){
				ok++;
				dp[i][{x1 + c, x2}] = 1;	
				path[i][x1 + c][x2] = path[i-1][x1][x2] + "B";
			}
			if(ok == 2){
				dp[i][{x1 + c, x2 + c}] = 1;	
				path[i][x1 + c][x2 + c] = path[i-1][x1][x2] + "G";
			}
		}
	}
	if(dp[n-1][{0, 0}]){
		cout << path[n-1][0][0];
	}else{
		cout << "impossible";
	}
}


void solve1(){
	int n; cin >> n;
	map<pair<int, int>, int> dp[n];
	dp[0][{0, 1}] = 1, dp[0][{1, 0}] = 1;
	dp[0][{1, 1}] = 1;
	vector< vector<int> > cnt(n, vector<int>(2, 0));
	cnt[0][0] = 1;
	for(int i = 1;i < n; i++){
		for(auto [pp, y] : dp[i-1]){
			int x1 = pp.ff, x2 = pp.ss;
			int ok = 0;
			int c = -1;
			if(x2 + c >= 0){
				ok++;
				dp[i][{x1, x2 + c}] = (dp[i][{x1, x2 + c}] + y) % mod;
			}
			if(x1 + c >= 0){
				ok++;
				dp[i][{x1 + c, x2}] = (dp[i][{x1 + c, x2}] + y) % mod;	
			}
			if(ok){
				cnt[i][1] = (cnt[i][1] + cnt[i-1][0] + cnt[i-1][1]) % mod;
			}
			if(ok == 2){
				dp[i][{x1 + c, x2 + c}] = (dp[i][{x1 + c, x2 + c}] + y) % mod;	
			}
			c = 1;
			cnt[i][0] = (cnt[i][0] + cnt[i-1][0] + cnt[i-1][1]) % mod;
			dp[i][{x1 + c, x2 + c}] = (dp[i][{x1 + c, x2 + c}] + y) % mod;
			dp[i][{x1 + c, x2}] = (dp[i][{x1 + c, x2}] + y) % mod;	
			dp[i][{x1, x2 + c}] = (dp[i][{x1, x2 + c}] + y) % mod;	
		}
	}
	cout << cnt[n-1][1] + cnt[n-1][0];
}

main(){
   ios::sync_with_stdio(0);
   cin.tie(0); cout.tie(0);
   cin >> P;
	int test; cin >> test;
	while(test--){
		if(P == 1)solve();
		else solve1();
		cout << '\n';
	}
	return 0;
}

Compilation message (stderr)

parentrises.cpp:96:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   96 | main(){
      | ^~~~

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