Submission #1107447

#	Time	Username	Problem	Language	Result	Execution time	Memory
1107447		vjudge1	Growing Vegetable is Fun 3 (JOI19_ho_t3)	C++17	15 / 100	485 ms	17740 KiB

joi2019_ho_t3

#include <bits/stdc++.h>

using namespace std;

#define int long long
#define sz(x) x.size()
#define pb push_back
#define F first
#define S second
#define nl '\n'

const int N = 2e5 - 1;
const int inf = 1e12;

bool ch( string s )
{
	for( int i = 1; i < sz(s); ++i )
		if( s[i] == s[i - 1] )
			return false;
	return true;
}

void solve()
{
	int n;
	string s;
	cin >>n >>s;
	int x, y, z;
	x = y = z = 0;
	vector< int >r, g;
	for( int i = 0; i < n; ++i )
	{
		if( s[i] == 'R' )
		{
			r.pb( i );
			++x;
		}
		if( s[i] == 'G' )
		{
			g.pb( i );
			++y;
		}
		if( s[i] == 'Y' )
			++z;
	}
	if( x - 1 > y + z || y - 1 > x + z || z - 1 > x + y )
	{
		cout <<-1 <<nl;
		return;
	}
	if( y + x == n )
	{
		if( y > x )
		{
			swap(x, y);
			swap(r, g);
		}
		int ans = 0;
		if( x > y )
		{
			int pos = 1;
			for( int i: g )
			{
				ans += abs(pos - i);
				pos += 2;
			}
		}
		else
		{
			int cnt1 = 0, cnt2 = 0, pos = 0;
			for( int i: r )
			{
				cnt1 += abs(i - pos);
				pos += 2;
			}
			pos = 0;
			for( int i: g )
			{
				cnt2 += abs(i - pos);
				pos += 2;
			}
			ans = min(cnt1, cnt2);
		}
		cout <<ans <<nl;
		return;
	}
	else
	{
		int ans = inf, cnt = 0;
		map<string, int>mp;
		queue< string >q;
		mp[s] = 0;
		q.push(s);
		while( !q.empty() )
		{
			++cnt;
			if( cnt > N )
			{
				cout <<-1 <<nl;
				return;
			}
			string v = q.front();
			q.pop();
			if( ch(v) )
			{
				ans = min(ans, (int)mp[v]);
				continue;
			}
			if( cnt > N )
			{
				cout <<-1 <<nl;
				return;
			}
			for( int i = 1; i < n; ++i )
			{
				string v1 = v;
				swap(v1[i], v1[i - 1]);
				if( !mp.count(v1) )
				{
					mp[v1] = mp[v] + 1;
					q.push(v1);
				}
			}
		}
		cout <<ans;
	}
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    int T = 1;
    // cin >>T;
    while( T-- )
    	solve();
}

Compilation message (stderr)

joi2019_ho_t3.cpp: In function 'bool ch(std::string)':
joi2019_ho_t3.cpp:17:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |  for( int i = 1; i < sz(s); ++i )
      |                    ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 55
• Subtask 3: 15 / 15
• Subtask 4: 0 / 25