Submission #109128

#	Time	Username	Problem	Language	Result	Execution time	Memory
109128		MetB	Miners (IOI07_miners)	C++14	100 / 100	305 ms	201052 KiB

miners

#include <iostream>
#include <cstdlib>
#include <string>
#include <set>
#include <map>
#include <algorithm>
#include <bitset>
#include <queue>
#include <math.h>
#include <stack>
#include <vector>
#include <string.h>
#include <random>
 
typedef long long ll;
 
const ll MOD = 1e9 + 7, INF = 1e18;
 
using namespace std;
 
int n;

struct state
{
	int a, b, c, d;
};



int encode (state s)
{
	return s.a * 64 + s.b * 16 + s.c * 4 + s.d;
}

state decode (int s)
{
	state a;
	a.a = s / 64;
	s %= 64;
	a.b = s / 16;
	s %= 16;
	a.c = s / 4;
	s %= 4;
	a.d = s;
	return a;
}

int value (state s, int a, bool left)
{
	int ans = 0;
	if (left)
	{
		if (s.a == 1 || s.b == 1 || a == 1) ans++;
		if (s.a == 2 || s.b == 2 || a == 2) ans++;
		if (s.a == 3 || s.b == 3 || a == 3) ans++;
	}
	else
	{
		if (s.c == 1 || s.d == 1 || a == 1) ans++;
		if (s.c == 2 || s.d == 2 || a == 2) ans++;
		if (s.c == 3 || s.d == 3 || a == 3) ans++;
	}

	return ans;
}

state transfer (state s, int k, bool left)
{
	if (left)
	{
		s.a = s.b;
		s.b = k;	
	}
	else
	{
		s.c = s.d;
		s.d = k;
	}

	return s;
}
 
int d[100000][256], u[100000][256];
 
int main ()
{
	cin >> n;
 
	string s;
 
	cin >> s;
 
	string h (1, s[0]);

	state en;
	if (s[0] == 'M') en.b = 1;
	if (s[0] == 'B') en.b = 2;
	if (s[0] == 'F') en.b = 3;
	en.a = en.c = en.d = 0;
 
	d[1][encode (en)] = 1;
	u[1][encode (en)] = 1;
 
	int mx = 1;
 
	for (int i = 1; i < s.length (); i++)
	{
		for (int j = 0; j < 256; j++)
		{
			if (!u[i][j]) continue;

			state dec = decode (j);
			int cur = 0;


			if (s[i] == 'M') cur = 1;
			if (s[i] == 'B') cur = 2;
			if (s[i] == 'F') cur = 3;

			int b = encode (transfer (dec, cur, true));

			u[i + 1][b] = 1;
			d[i + 1][b] = max (d[i + 1][b], value (dec, cur, true) + d[i][j]);

			mx = max (mx, d[i + 1][b]);

			b = encode (transfer (dec, cur, false));

			u[i + 1][b] = 1;
			d[i + 1][b] = max (d[i + 1][b], value (dec, cur, false) + d[i][j]);

			mx = max (mx, d[i + 1][b]);
		}
	}
 
	cout << mx;
}

Compilation message (stderr)

miners.cpp: In function 'int main()':
miners.cpp:106:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 1; i < s.length (); i++)
                  ~~^~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 7 / 7
• Subtask 7: 8 / 8
• Subtask 8: 8 / 8
• Subtask 9: 8 / 8
• Subtask 10: 8 / 8
• Subtask 11: 8 / 8
• Subtask 12: 8 / 8