Submission #1047681

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047681		Tsovak	Sprinklers (CEOI24_sprinklers)	C++17	100 / 100	119 ms	2156 KiB

Main

// -------------------- Includes -------------------- //
#define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <stdio.h>
#include <cstdlib>
#include <stdlib.h>
#include <array>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <math.h>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <list>
#include <iterator>
#include <numeric>
#include <complex>
#include <tuple>
#include <utility>
#include <cassert>
#include <assert.h>
#include <climits>
#include <limits.h>
#include <ctime>
#include <time.h>
#include <random>
#include <chrono>
#include <fstream>
using namespace std;

// -------------------- Typedefs -------------------- //

typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;

// -------------------- Defines -------------------- //

#define pr pair
#define mpr make_pair
#define first
#define ss second

#define mset multiset
#define mmap multimap
#define uset unordered_set
#define umap unordered_map
#define umset unordered_multiset
#define ummap unordered_multimap
#define pqueue priority_queue

#define sz(x) (int((x).size()))
#define len(x) (int((x).length()))
#define all(x) (x).begin(), (x).end()
#define clr(x) (x).clear()

#define ft front
#define bk back
#define pf push_front
#define pb push_back
#define popf pop_front
#define popb pop_back

#define lb lower_bound
#define ub upper_bound
#define bs binary_search

// -------------------- Constants -------------------- //

const int MAX = int(1e9 + 5);
const ll MAXL = ll(1e18 + 5);
const ll MOD = ll(1e9 + 7);
const ll MOD2 = ll(998244353);

// -------------------- Functions -------------------- //

void fastio()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	return;
}

void precision(int x)
{
	cout << fixed << setprecision(x);
	return;
}

ll gcd0(ll a, ll b)
{
	while (b) {
		a %= b;
		swap(a, b);
	}
	return a;
}

ll lcm0(ll a, ll b)
{
	return a / gcd0(a, b) * b;
}

bool is_prime(ll a)
{
	if (a == 1) return false;
	for (ll i = 2; i * i <= a; i++) if (a % i == 0) return false;
	return true;
}

bool is_square(ll a)
{
	ll b = ll(sqrtl(ld(a)));
	return (b * b == a);
}

bool is_cube(ll a)
{
	ll b = ll(cbrtl(ld(a)));
	return (b * b * b == a);
}

int digit_sum(ll a)
{
	int sum = 0;
	while (a) {
		sum += int(a % 10);
		a /= 10;
	}
	return sum;
}

ll binpow(ll a, int b)
{
	ll ans = 1;
	while (b) {
		if (b & 1) ans *= a;
		b >>= 1;
		a *= a;
	}
	return ans;
}

ll binpow_mod(ll a, ll b, ll mod)
{
	ll ans = 1;
	while (b) {
		if (b & 1) ans = (ans * a) % mod;
		b >>= 1;
		a = (a * a) % mod;
	}
	return ans;
}

ll factorial(int a)
{
	ll ans = 1;
	for (int i = 2; i <= a; i++) ans *= ll(i);
	return ans;
}

ll factorial_mod(int a, ll mod)
{
	ll ans = 1;
	for (int i = 2; i <= a; i++) ans = (ans * ll(i)) % mod;
	return ans;
}

// -------------------- Solution -------------------- //

const int N = 100005, M = 100005;
int a[N], b[M];
bool ans[N];
int n, m;

int dp[N];
int from[N];

bool covers(int l, int r, int e) { return (l <= b[e] && b[e] <= r); }

bool check(int h)
{
	int i, j;

	for (i = 0; i <= n; i++) {
		dp[i] = 0;
		from[i] = -1;
	}

	dp[0] = 1;

	for (i = 0; i < n; i++) {
		if (dp[i + 1] < dp[i]) {
			dp[i + 1] = dp[i];
			from[i + 1] = 0;
		}

		if (covers(a[i + 1] - h, a[i + 1], dp[i])) {
			j = ub(b + 1, b + m + 1, a[i + 1]) - b;

			if (dp[i + 1] < j) {
				dp[i + 1] = j;
				from[i + 1] = 1;
			}
		}

		if (covers(a[i + 1], a[i + 1] + h, dp[i])) {
			j = ub(b + 1, b + m + 1, a[i + 1] + h) - b;

			if (dp[i + 1] < j) {
				dp[i + 1] = j;
				from[i + 1] = 2;
			}
		}


		if (i + 2 <= n && a[i + 2] - a[i + 1] < h && covers(a[i + 2] - h, a[i + 1] + h, dp[i])) {
			j = ub(b + 1, b + m + 1, a[i + 1] + h) - b;

			if (dp[i + 2] < j) {
				dp[i + 2] = j;
				from[i + 2] = 3;
			}
		}
	}

	return (dp[n] == m + 1);
}

void solve()
{
	int i, j;

	cin >> n >> m;

	for (i = 1; i <= n; i++) cin >> a[i];
	for (i = 1; i <= m; i++) {
		cin >> b[i];

		if (i > 1 && b[i] == b[i - 1]) {
			i--;
			m--;
		}
	}

	if (n == 1) {
		if (a[1] <= b[1]) cout << b[m] - a[1] << "\nR\n";
		else if (b[m] <= a[1]) cout << a[1] - b[1] << "\nL\n";
		else cout << "-1\n";

		return;
	}


	int l = 0, r = 1e9, mid;

	while (l < r) {
		mid = (l + r) / 2;

		if (check(mid)) r = mid;
		else l = mid + 1;
	}

	check(l);

	i = n;
	while (i) {
		if (from[i] <= 1) i--;
		else if (from[i] == 2) {
			ans[i] = 1;
			i--;
		}
		else {
			ans[i - 1] = 1;
			i -= 2;
		}
	}


	cout << l << "\n";
	for (i = 1; i <= n; i++) cout << (ans[i] ? 'R' : 'L');
	cout << "\n";

	return;
}

void precalc()
{
	return;
}

int main()
{
	fastio();

	precalc();

	int tests = 1, tc;
	//cin >> tests;
	for (tc = 1; tc <= tests; tc++) {
		solve();
	}

	return 0;
}

/*
	# # # #   # # # #   # # # #   #       #    #       #     #
	   #      #         #     #    #     #    # #      #   #
	   #      # # # #   #     #     #   #    #   #     # #
	   #            #   #     #      # #    # # # #    #   #
	   #      # # # #   # # # #       #    #       #   #     #
*/

Compilation message (stderr)

Main.cpp: In function 'void solve()':
Main.cpp:245:9: warning: unused variable 'j' [-Wunused-variable]
  245 |  int i, j;
      |         ^

• Subtask 0: 0 / 0
• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 17 / 17
• Subtask 4: 27 / 27
• Subtask 5: 47 / 47