Submission #1214202

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214202		MateiKing80	Sprinklers (CEOI24_sprinklers)	C++20	100 / 100	552 ms	6680 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int inf = 1e9;

int main() {
    int n, m;
    cin >> n >> m;
    vector<int> spr;
    vector<int> fl;
    map<int,int> fli;
    for (int i = 0; i < n; i ++) {
        int x;
        cin >> x;
        spr.push_back(x);
    }
    for (int i = 0; i < m; i ++) {
        int x;
        cin >> x;
        fl.push_back(x);
        fli[x] = i;
    }
    fli[2 * inf] = m;
    int lower = 0, upper = inf + 2;
    while (1) {
        int kval = (lower + upper) / 2 - 1;
        if (lower + 1 >= upper) {
            if (lower == inf + 1) {
                cout << "-1\n";
                return 0;
            } else {
                kval = lower;
            }
        }
        vector<pair<int, int>> dp(n + 1);
        for (int i = 0; i < n; i ++) {
            pair<int, int> curval = dp[i];
            dp[i + 1] = max(dp[i + 1], {curval.first, 0});
            if (curval.first < m) {
                if (fl[curval.first] >= spr[i] - kval) {
                    dp[i + 1] = max(dp[i + 1], {fli.upper_bound(spr[i])->second, -1});
                }
                if (fl[curval.first] >= spr[i]) {
                    dp[i + 1] = max(dp[i + 1], {fli.upper_bound(spr[i] + kval)->second, 1});
                }
                if (i + 1 < n && spr[i] <= spr[i] + kval) {
                    if (fl[curval.first] >= spr[i + 1] - kval) {
                        dp[i + 2] = max(dp[i + 2], {fli.upper_bound(spr[i] + kval)->second, 2});
                    }
                }
            }
        }
        if (lower + 1 >= upper) {
            cout << lower << '\n';
            string rec(n, ' ');
            int ind = n;
            while (ind) {
                if (dp[ind].second == -1) {
                    rec[ind - 1] = 'L';
                    ind --;
                } else if (dp[ind].second == 1) {
                    rec[ind - 1] = 'R';
                    ind --;
                } else if (dp[ind].second == 2) {
                    rec[ind - 1] = 'L';
                    rec[ind - 2] = 'R';
                    ind -= 2;
                } else {
                    rec[ind - 1] = 'L';
                    ind --;
                }
            }
            cout << rec << '\n';
            return 0;
        }
        if (dp.back().first == m) {
            upper = kval + 1;
        } else {
            lower = kval + 1;
        }
    }
}

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