Submission #386167

#	Time	Username	Problem	Language	Result	Execution time	Memory
386167		idontreallyknow	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	1000 ms	133484 KiB

joioi

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class A> ostream& operator<<(ostream &cout, vector<A> const &v) {cout << "["; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]";};
template<class A, class B> ostream& operator<<(ostream &cout, const pair<A,B> &x) {return cout << "(" <<x.first << ", " << x.second << ")";};
template <class T> void pv(T a, T b) {cerr << "["; for (T i = a; i != b; ++i) cerr << *i << " "; cerr << "]\n";}
void _print() {cerr << "]\n";}
template <class T, class... V> void _print(T t, V... v) {cerr << t; if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#define fi first
#define se second
#define SZ(x) (int)((x).size())
#define pii pair<int,int>
const int mx = 2e3+5;
int n,m,a[mx][mx], lma[mx][mx], lmi[mx][mx], rma[mx][mx], rmi[mx][mx], small = INT_MAX, large = INT_MIN, ans;
void recalc() {
	for (int q = 0; q < n; q++) {
		lma[q][0] = a[q][0];
		lmi[q][0] = a[q][0];
		rma[q][m-1] = a[q][m-1];
		rmi[q][m-1] = a[q][m-1];
		for (int w = 1; w < m; w++) {
			lma[q][w] = max(lma[q][w-1], a[q][w]);
			lmi[q][w] = min(lmi[q][w-1], a[q][w]);
		}
		for (int w = m-2; w >= 0; w--) {
			rma[q][w] = max(rma[q][w+1], a[q][w]);
			rmi[q][w] = min(rmi[q][w+1], a[q][w]);
		}
	}
}
bool check(int x) {
	int lasma = 0, lasmi = 0;
	bool okma = true, okmi = true;
	for (int q = 0; q < n; q++) {
		for (int w = lasma; w < m; w++) {
			if (w < m-1) {
				if (lma[q][w]-small <= x && large-rmi[q][w+1] <= x) {
					lasma = w;
					break;
				}
			} else {
				if (lma[q][w]-small <= x) lasma = w;
				else okma = false;
			}
		}
		for (int w = lasmi; w < m; w++) {
			if (w < m-1) {
				if (large-lmi[q][w] <= x && rma[q][w+1]-small <= x) {
					lasmi = w;
					break;
				}
			} else {
				if (large-lmi[q][w] <= x) lasmi = w;
				else okmi = false;
			}
		}
	}
	if (okmi || okma) return true;
	return false;
}
const int inf = 1e9;
void work() {
	int lo = -1, hi = inf+1;
	while (hi - lo > 1) {
		int mid = (lo+hi)/2;
		if(check(mid)) hi = mid;
		else lo = mid;
	}
	ans = min(ans, hi);
}
void printa() {
	cout << "BEGIN\n";
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			cout << a[q][w] << " ";
		}
		cout << "\n";
	}
}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n >> m;
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			cin >> a[q][w];
			small = min(small, a[q][w]);
			large = max(large, a[q][w]);
		}
	}
	ans = large-small;
	recalc();
	work();
	int tmp[mx][mx];
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			tmp[w][q] = a[q][w];
		}
	}
	swap(n,m);
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			a[q][w] = tmp[q][w];
		}
	}
	recalc();
	work();
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			tmp[m-1-w][q] = a[q][w];
		}
	}
	swap(n,m);
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			a[q][w] = tmp[q][w];
		}
	}
	recalc();
	work();
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			tmp[w][q] = a[q][w];
		}
	}
	swap(n,m);
	for (int q = 0; q < n; q++) {
		for (int w = 0; w < m; w++) {
			a[q][w] = tmp[q][w];
		}
	}
	recalc();
	work();
	cout << ans << "\n";
	return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 45 / 45
• Subtask 3: 40 / 40