Submission #62245

#	Time	Username	Problem	Language	Result	Execution time	Memory
62245		qkxwsm	Dango Maker (JOI18_dango_maker)	C++17	100 / 100	674 ms	18832 KiB

dango_maker

/*
PROG: source
LANG: C++11
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
 */
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
    int operator()(int x) const
	{
		x ^= (x >> 20) ^ (x >> 12);
    	return x ^ (x >> 7) ^ (x >> 4);
	}
	int operator()(long long x) const
	{
		return x ^ (x >> 32);
	}
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T> using hashtable = gp_hash_table<T, T, chash>;

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
	{
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
template<class T>
T normalize(T x, T mod = 1000000007)
{
	return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
	return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
	return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 3013
#define MAXM 11000013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N, M, K, E = 2;
int S, T;
short grid[MAXN][MAXN];
int ok[MAXN][2];
int lvl[MAXM];
bool color[MAXM];
int to[MAXM], cap[MAXM], nxt[MAXM], head[MAXM];
int ans;

void addedge(int u, int v, int f)
{
    to[E] = v; cap[E] = f;
    nxt[E] = head[u]; head[u] = E;
    E++;
    to[E] = u; cap[E] = 0;
    nxt[E] = head[v]; head[v] = E;
    E++;
}
bool bfs()
{
    for (int i = 0; i < K; i++)
    {
        lvl[i] = -1;
    }
    queue<int> q;
    lvl[S] = 0;
    q.push(S);
    while(!q.empty())
    {
        int u = q.front();
        q.pop();
        for (int e = head[u]; e; e = nxt[e])
        {
            int v = to[e];
            if (cap[e] > 0 && lvl[v] == -1)
            {
                lvl[v] = lvl[u] + 1;
                q.push(v);
                if (v == T)
                {
                    return true;
                }
            }
        }
    }
    return false;
}
int aug(int u, int f)
{
    if (u == T)
    {
        return f;
    }
    int rem = f, gain = 0;
    for (int e = head[u]; e; e = nxt[e])
    {
        int v = to[e];
        if (cap[e] && lvl[v] == lvl[u] + 1)
        {
            gain = aug(v, min(rem, cap[e]));
			cap[e] -= gain;
			cap[e ^ 1] += gain;
			rem -= gain;
        }
    }
    return f - rem;
}
int dinic()
{
    int res = 0;
    while(bfs())
    {
        res += aug(S, INF);
    }
    return res;
}
int matching()
{
    S = K; T = K + 1;
    for (int i = 0; i < K; i++)
    {
        if (color[i])
        {
            addedge(i, T, 1);
        }
        else
        {
            addedge(S, i, 1);
        }
    }
    K += 2;
    int res = dinic();
    return res;
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	srand(time(0));
	//	cout << fixed << setprecision(10);
	//	cerr << fixed << setprecision(10);
	if (fopen("input.in", "r"))
	{
		freopen ("input.in", "r", stdin);
		freopen ("output.out", "w", stdout);
	}
    cin >> N >> M;
    for (int i = 0; i < N; i++)
    {
        string temps;
        cin >> temps;
        for (int j = 0; j < M; j++)
        {
            if (temps[j] == 'R')
            {
                grid[i][j] = -1;
            }
            if (temps[j] == 'G')
            {
                grid[i][j] = 0;
            }
            if (temps[j] == 'W')
            {
                grid[i][j] = 1;
            }
        }
    }
    for (int s = 0; s < N + M; s++)
    {
        for (int i = 0; i < N; i++)
        {
            int j = s - i;
            if (j < 0 || j >= M)
            {
                continue;
            }
            ok[i][0] = ok[i][1] = -1;
        }
        for (int i = 0; i < N; i++)
        {
            int j = s - i;
            if (j < 0 || j >= M)
            {
                continue;
            }
            if (grid[i][j] == -1 && grid[i][j + 1] == 0 && grid[i][j + 2] == 1)
            {
                ok[i][1] = K;
                color[K] = true;
                K++;
            }
            if (grid[i][j] == -1 && grid[i + 1][j] == 0 && grid[i + 2][j] == 1)
            {
                ok[i][0] = K;
                color[K] = false;
                K++;
            }
        }
        for (int i = 0; i < N; i++)
        {
            int j = s - i;
            if (ok[i][0] == -1)
            {
                continue;
            }
            if (ok[i][1] != -1)
            {
                addedge(ok[i][0], ok[i][1], INF);
            }
            if (i + 1 < N && j - 1 >= 0 && ok[i + 1][1] != -1)
            {
                addedge(ok[i][0], ok[i + 1][1], INF);
            }
            if (i + 2 < N && j - 2 >= 0 && ok[i + 2][1] != -1)
            {
                addedge(ok[i][0], ok[i + 2][1], INF);
            }
        }
        ans += K;
        ans -= matching();
        E = 2;
        for (int i = 0; i < K; i++)
        {
            head[i] = 0;
        }
        K = 0;
    }
    cout << ans << '\n';
	//	cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Compilation message (stderr)

dango_maker.cpp: In function 'int32_t main()':
dango_maker.cpp:247:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("input.in", "r", stdin);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
dango_maker.cpp:248:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("output.out", "w", stdout);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 20 / 20
• Subtask 3: 67 / 67