結果

問題 No.2855 Move on Grid
ユーザー 👑 binap
提出日時 2024-08-25 13:58:37
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 957 ms / 3,000 ms
コード長 5,221 bytes
コンパイル時間 4,651 ms
コンパイル使用メモリ 269,148 KB
最終ジャッジ日時 2025-02-24 01:02:44
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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ファイルパターン 結果
other AC * 40
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ソースコード

diff # 

#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef long double ld;
typedef pair<int, int> P;

ostream& operator<<(ostream& os, const modint& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}
template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}
template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;}
template<typename T> ostream& operator<<(ostream& os, const set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename S, auto op, auto e> ostream& operator<<(ostream& os, const atcoder::segtree<S, op, e>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}
template<typename S, auto op, auto e, typename F, auto mapping, auto composition, auto id> ostream& operator<<(ostream& os, const atcoder::lazy_segtree<S, op, e, F, mapping, composition, id>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}

template<typename T> void chmin(T& a, T b){a = min(a, b);}
template<typename T> void chmax(T& a, T b){a = max(a, b);}

const int INF = 1000000000;

struct Edge_BFS01{
	int from, to;
	int cost;
	Edge_BFS01(int from, int to, int cost) : from(from), to(to), cost(cost) {};
};

struct BFS01{
	int n, m;
	vector<bool> initialized;
	vector<Edge_BFS01> E;
	vector<vector<int>> G;
	map<int, vector<int>> dist;
	map<int, vector<int>> idx;
	BFS01(int _n) : n(_n), m(0), initialized(n, false), G(n){}
	void add_edge(int from, int to, int cost){
		assert(cost == 0 or cost == 1);
		Edge_BFS01 e(from, to, cost);
		E.push_back(e);
		G[from].emplace_back(m);
		m++;
	}
	void add_grid(int h, int w, vector<string> s){
		assert(int(s.size()) == h);
		assert(int(s[0].size()) == w);
		rep(y, h){
			rep(x, w - 1){
				if(s[y][x] != '#' and s[y][x + 1] != '#'){
					add_edge(y * w + x, y * w + (x + 1), 1);
					add_edge(y * w + (x + 1), y * w + x, 1);
				}
			}
		}
		rep(x, w){
			rep(y, h - 1){
				if(s[y][x] != '#' and s[y + 1][x] != '#'){
					add_edge(y * w + x, (y + 1) * w + x, 1);
					add_edge((y + 1) * w + x, y * w + x, 1);
				}
			}
		}
	}
	void calc(int s){
		initialized[s] = true;
		dist[s] = vector<int>(n, INF);
		idx[s] = vector<int>(n, -1);
		deque<tuple<int, int ,int>> de;
		de.emplace_back(0, s, -1);
		while(de.size()){
			auto [cost, from, index] = de.front(); de.pop_front();
			if(dist[s][from] <= cost) continue;
			dist[s][from] = cost;
			idx[s][from] = index;
			for(int index : G[from]){
				int to = E[index].to;
				int cost_plus = E[index].cost;
				if(dist[s][to] <= cost + cost_plus) continue;
				if(cost_plus == 0) de.emplace_front(cost + cost_plus, to, index);
				if(cost_plus == 1) de.emplace_back(cost + cost_plus, to, index);
			}
		}
	}
	int farthest(int s){
		if(!initialized[s]) calc(s);
		int idx = 0;
		rep(i, n) if(dist[s][i] > dist[s][idx]) idx = i;
		return idx;
	}
	int get_dist(int s, int t){
		if(!initialized[s]) calc(s);
		return dist[s][t];
	}
	vi restore(int s, int t){
		if(!initialized[s]) calc(s);
		if(dist[s][t] == INF) return vi(0);
		vi res;
		while(idx[s][t] != -1){
			auto e = E[idx[s][t]];
			res.push_back(idx[s][t]);
			t = e.from;
		}
	reverse(res.begin(), res.end());
	return res;
	}
};

int main(){
	int n, m, k;
	cin >> n >> m >> k;
	vector<vector<int>> a(n, vector<int>(m));
	cin >> a;
	int ok = 0, ng = INF + 1;
	while(ng - ok > 1){
		int mid = (ok + ng) / 2;
		BFS01 graph(n * m + 1);
		int sv = n * m;
		rep(y, n) rep(x, m - 1){
			{
				int cost = 0;
				if(a[y][x + 1] < mid) cost = 1;
				graph.add_edge(y * m + x, y * m + (x + 1), cost);
			}
			{
				int cost = 0;
				if(a[y][x] < mid) cost = 1;
				graph.add_edge(y * m + (x + 1), y * m + x, cost);
			}
		}
		rep(y, n - 1) rep(x, m){
			{
				int cost = 0;
				if(a[y + 1][x] < mid) cost = 1;
				graph.add_edge(y * m + x, (y + 1) * m + x, cost);
			}
			{
				int cost = 0;
				if(a[y][x] < mid) cost = 1;
				graph.add_edge((y + 1) * m + x, y * m + x, cost);
			}
		}
		{
			{
				int cost = 0;
				if(a[0][0] < mid) cost = 1;
				graph.add_edge(sv, 0, cost);
			}
		}
		int tot = graph.get_dist(sv, n * m - 1);
		if(tot <= k) ok = mid;
		else ng = mid;
	}
	cout << ok << "\n";
	return 0;
}
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