Submission #1105053

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105053		SalihSahin	Sprinklers (CEOI24_sprinklers)	C++14	100 / 100	98 ms	8776 KiB

Main

#include <bits/stdc++.h>
#define pb push_back
#define int long long
using namespace std;

const int mod = 1e9 + 7;
const int inf = 1e15;
const int N = 1e5+5;

int32_t main(){
    cin.tie(0); cout.tie(0);
    ios_base::sync_with_stdio(false);
    int n, m;
    cin>>n>>m;
    vector<int> s(n), f(m);
    for(int i = 0; i < n; i++){
        cin>>s[i];
    }
    for(int i = 0; i < m; i++){
        cin>>f[i];
    }

    vector<int> right(n), us(n);
    int l = 0, r = mod;
    while(l < r){
        int mid = (l + r)/2;

        int ind = 0;
        for(int i = 0; i < n; i++){
            while(ind < m && s[i] + mid >= f[ind]) ind++;
            right[i] = ind; // sağı sulayarak alamayacağımız ilk çiçek
        }
        ind = 0;
        for(int i = 0; i < n; i++){
            while(ind < m && s[i] >= f[ind]) ind++;
            us[i] = ind; // benden büyük ilk çiçek
        }

        vector<int> dp(n+1); // dp[i] => ilk i tane sprinkle ile maximum alınabilecek flower prefixi
        for(int i = 0; i < n; i++){
            dp[i+1] = max(dp[i+1], dp[i]);
            if(dp[i] == m) continue;
            int j = dp[i];

            if(s[i] - mid <= f[j]){ // sola
                dp[i+1] = max(dp[i+1], us[i]);
            }
            if(f[j] >= s[i]){
                dp[i+1] = max(dp[i+1], right[i]);
            }
            if(i < n-1 && f[j] <= s[i+1] && s[i+1] - mid <= f[j]){
                dp[i+2] = max({dp[i+2], right[i]});
            }
        }

        if(dp[n] == m) r = mid;
        else l = mid + 1;
    }

    int ans = l;
    if(ans == mod){
        cout<<-1<<endl;
        return 0;
    }
    cout<<ans<<endl;

    int ind = 0;
    for(int i = 0; i < n; i++){
        while(ind < m && s[i] + ans >= f[ind]) ind++;
        right[i] = ind; // sağı sulayarak alabileceğim son çiçek + 1
    }
    ind = 0;
    for(int i = 0; i < n; i++){
        while(ind < m && s[i] >= f[ind]) ind++;
        us[i] = ind; // benden büyük ilk çiçek
    }

    vector<int> dp(n+1); // dp[i] => ilk i tane sprinkle ile maximum alınabilecek flower prefixi
    vector<int> par(n+1), ptype(n+1);
    par[0] = -1;

    for(int i = 0; i < n; i++){
        if(dp[i+1] < dp[i]){
            dp[i+1] = dp[i];
            par[i+1] = i;
            ptype[i+1] = 0;
        }
        if(dp[i] == m) continue;

        int j = dp[i];

        if(s[i] - ans <= f[j]){ // sola
            if(dp[i+1] < us[i]){
                dp[i+1] = us[i];
                par[i+1] = i;
                ptype[i+1] = 0;
            }
        }
        if(f[j] >= s[i]){
            if(dp[i+1] < right[i]){
                dp[i+1] = right[i];
                par[i+1] = i;
                ptype[i+1] = 1;
            }
        }
        if(i < n-1 && f[j] <= s[i+1] && s[i+1] - ans <= f[j]){
            if(dp[i+2] < right[i]){
                dp[i+2] = right[i];
                par[i+2] = i;
                ptype[i+2] = 2;
            }
        }
    }

    vector<int> d(n+1);
    for(int i = n; i > 0; i = par[i]){
        if(par[i] == i-2){
            d[i-1] = 0;
            d[i-2] = 1;
        }
        else if(ptype[i] == 1){
            d[i-1] = 1;
        }
        else if(ptype[i] == 0){
            d[i-1] = 0;
        }
    }

    for(int i = 0; i < n; i++){
        if(d[i]) cout<<"R";
        else cout<<"L";
    }
    cout<<endl;   
    return 0;
}

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