Submission #67383199

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Source Code Expand

/**
 *    author:  otera
**/
#include<bits/stdc++.h>

namespace otera {}
using namespace std;
using namespace otera;

struct io_setup {
    io_setup(int precision = 20) {
        ios::sync_with_stdio(false);
        cin.tie(0);
        cout << fixed << setprecision(precision);
    }
} io_setup_ {};

using ll = long long;
using ld = long double;
using ull = unsigned long long;
using i128 = __int128_t;
using u128 = __uint128_t;
#define repa(i, n) for(int i = 0; i < (n); ++ i)
#define repb(i, a, b) for(int i = (a); i < (b); ++ i)
#define repc(i, a, b, c) for(int i = (a); i < (b); i += (c))
#define overload4(a, b, c, d, e, ...) e
#define overload3(a, b, c, d, ...) d
#define rep(...) overload4(__VA_ARGS__, repc, repb, repa)(__VA_ARGS__)
#define rep1a(i, n) for(int i = 1; i <= (n); ++ i)
#define rep1b(i, a, b) for(int i = (a); i <= (b); ++ i)
#define rep1c(i, a, b, c) for(int i = (a); i <= (b); i += (c))
#define rep1(...) overload4(__VA_ARGS__, rep1c, rep1b, rep1a)(__VA_ARGS__)
#define rev_repa(i, n) for(int i=(n)-1;i>=0;i--)
#define rev_repb(i, a, b) for(int i=(b)-1;i>=(a);i--)
#define rev_rep(...) overload3(__VA_ARGS__, rev_repb, rev_repa)(__VA_ARGS__)
#define rev_rep1a(i, n) for(int i=(n);i>=1;i--)
#define rev_rep1b(i, a, b) for(int i=(b);i>=(a);i--)
#define rev_rep1(...) overload3(__VA_ARGS__, rev_rep1b, rev_rep1a)(__VA_ARGS__)
#define for_subset(t, s) for(ll t = (s); t >= 0; t = (t == 0 ? -1 : (t - 1) & (s)))
typedef pair<int, int> P;
typedef pair<ll, ll> LP;
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define eb emplace_back
#define mkp make_pair
#define mkt make_tuple
#define fr first
#define sc second
#define all(c) std::begin(c), std::end(c)
#define rall(c) std::rbegin(c), std::rend(c)
#define lb(c, x) distance(std::begin(c), lower_bound(all(c), (x)))
#define ub(c, x) distance(std::begin(c), upper_bound(all(c), (x)))
#define Sort(a) sort(all(a))
#define Rev(a) reverse(all(a))
#define Uniq(a) sort(all(a));(a).erase(unique(all(a)),std::end(a))
#define si(c) (int)(c).size()
inline ll popcnt(ull a){ return __builtin_popcountll(a); }
#define kth_bit(x, k) ((x>>k)&1)
#define unless(A) if(!(A))
#define elif else if
ll modulo(ll n, ll d){ return (n % d + d) % d; };
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll intpow(ll a, ll b, ll m) {ll ans = 1; while(b){ if(b & 1) (ans *= a) %= m; (a *= a) %= m; b /= 2; } return ans; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template <typename T> constexpr inline int pow_m1(T n) { return -(n & 1) | 1; }
template <typename T> constexpr inline T fld(const T x, const T y) { return (x ^ y) >= 0 ? x / y : (x - (y + pow_m1(y >= 0))) / y; }
template <typename T> constexpr inline T cld(const T x, const T y) { return (x ^ y) <= 0 ? x / y : (x + (y + pow_m1(y >= 0))) / y; }
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define ULL(...) ull __VA_ARGS__;in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__;in(__VA_ARGS__)
#define vec(type,name,...) vector<type>name(__VA_ARGS__)
#define VEC(type,name,size) vector<type>name(size);in(name)
#define vv(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define VV(type,name,h,w) vector<vector<type>>name(h,vector<type>(w));in(name)
#define vvv(type,name,h,w,...) vector<vector<vector<type>>>name(h,vector<vector<type>>(w,vector<type>(__VA_ARGS__)))
template <class T> using vc = vector<T>;
template <class T> using vvc = vector<vc<T>>;
template <class T> using vvvc = vector<vvc<T>>;
template <class T> using vvvvc = vector<vvvc<T>>;
template <class T> using pq = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vector<T>, greater<T>>;
template <class T, class U> using umap = unordered_map<T, U>;
template<class T> void scan(T& a){ cin >> a; }
template<class T> void scan(vector<T>& a){ for(auto&& i : a) scan(i); }
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){ scan(head); in(tail...); }
void print(){ cout << ' '; }
template<class T> void print(const T& a){ cout << a; }
template<class T> void print(const vector<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ cout << ' '; print(*i); } }
int out(){ cout << '\n'; return 0; }
template<class T> int out(const T& t){ print(t); cout << '\n'; return 0; }
template<class Head, class... Tail> int out(const Head& head, const Tail&... tail){ print(head); cout << ' '; out(tail...); return 0; }
#define CHOOSE(a) CHOOSE2 a
#define CHOOSE2(a0,a1,a2,a3,a4,x,...) x
#define debug_1(x1) cout<<#x1<<": "<<x1<<endl
#define debug_2(x1,x2) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<endl
#define debug_3(x1,x2,x3) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<endl
#define debug_4(x1,x2,x3,x4) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<", "#x4<<": "<<x4<<endl
#define debug_5(x1,x2,x3,x4,x5) cout<<#x1<<": "<<x1<<", "#x2<<": "<<x2<<", "#x3<<": "<<x3<<", "#x4<<": "<<x4<<", "#x5<<": "<<x5<<endl
#ifdef DEBUG
#define debug(...) CHOOSE((__VA_ARGS__,debug_5,debug_4,debug_3,debug_2,debug_1,~))(__VA_ARGS__)
#define dump(...) { print(#__VA_ARGS__); print(":"); out(__VA_ARGS__); }
#else
#define debug(...)
#define dump(...)
#endif

int n, m;
vc<string> s;

vc<P> final_ans;

const int inf = 1e9 + 7;

const int dx[4] = {0, 1, 0, -1};
const int dy[4] = {1, 0, -1, 0};

bool inside(int x, int y) {
    return 0 <= x and x < n and 0 <= y and y < n;
}

void init() {
    in(n, m);
    s.resize(n);
    rep(i, n) {
        in(s[i]);
    }
}

void output() {
    int sz = si(final_ans);
    assert(sz == n * n - m);
    rep(i, sz) {
        out(final_ans[i].fr, final_ans[i].sc);
    }
}

void solver1() {
    int sz = n * n - m;

    auto check = [&](int x, int y) -> bool {
        rep(k, 4) {
            int nx = x + dx[k], ny = y + dy[k];
            if(!inside(nx, ny) or s[nx][ny] == '#') {
                return false;
            }
        }
        return true;
    };

    rep(_, sz) {
        int flag = 0;
        rep(x, n) {
            rep(y, n) {
                if(!flag and s[x][y] == '.' and check(x, y)) {
                    flag = 1;
                    final_ans.eb(x, y);
                    s[x][y] = '#';
                }
            }
        }
        rep(x, n) {
            rep(y, n) {
                if(!flag and s[x][y] == '.') {
                    flag = 1;
                    final_ans.eb(x, y);
                    s[x][y] = '#';
                }
            }
        }
    }
}

void solver2() {
    int sz = n * n - m;

    vvc<ld> dp(n, vc<ld>(n, 0.0));
    rep(x, n) {
        rep(y, n) {
            dp[x][y] = 1.0 / (ld)(n * n);
        }
    }

    vvc<int> g_x(n), g_y(n);
    rep(x, n) {
        g_x[x].eb(-1);
        g_x[x].eb(n);
    }
    rep(y, n) {
        g_y[y].eb(-1);
        g_y[y].eb(n);
    }
    rep(x, n) {
        rep(y, n) {
            if(s[x][y] == '.') continue;
            g_x[x].eb(y);
            g_y[y].eb(x);
        }
    }
    rep(x, n) Sort(g_x[x]);
    rep(y, n) Sort(g_y[y]);

    rep(_, sz) {
        ld cur = inf;
        int pos_x = -1, pos_y = -1;
        rep(x, n) {
            rep(y, n) {
                if(s[x][y] == '#') continue;
                if(chmin(cur, dp[x][y])) {
                    pos_x = x, pos_y = y;
                }
            }
        }
        assert(pos_x != -1 and pos_y != -1);
        assert(s[pos_x][pos_y] == '.');

        s[pos_x][pos_y] = '#';
        dp[pos_x][pos_y] = 0.0;
        final_ans.eb(pos_x, pos_y);

        g_x[pos_x].eb(pos_y);
        g_y[pos_y].eb(pos_x);
        Sort(g_x[pos_x]);
        Sort(g_y[pos_y]);

        vvc<ld> ndp(n, vc<ld>(n, 0.0));

        auto nxt = [&](int x, int y) -> vc<P> {
            vc<P> ret;
            {
                int id = ub(g_x[x], y);
                // assert(1 <= id and id < si(g_x[x]));
                ret.eb(x, g_x[x][id - 1] + 1);
                ret.eb(x, g_x[x][id] - 1);
            }
            {
                int id = ub(g_y[y], x);
                // assert(1 <= id and id < si(g_y[y]));
                ret.eb(g_y[y][id - 1] + 1, y);
                ret.eb(g_y[y][id] - 1, y);
            }
            return ret;
        };

        rep(x, n) {
            rep(y, n) {
                if(s[x][y] == '#') continue;
                vc<P> ns = nxt(x, y);
                for(auto [nx, ny]: ns) {
                    assert(inside(nx, ny));
                    ndp[nx][ny] += dp[x][y] / (ld)4.0;
                }
            }
        }

        swap(dp, ndp);
    }
}

void solve() {
    init();
    solver2();
    output();
}

signed main() {
    int testcase = 1;
    // in(testcase);
    while(testcase--) solve();
    return 0;
}

Submission Info

Judge Result