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Submission #1074925

# Submission time Handle Problem Language Result Execution time Memory
1074925 2024-08-25T16:40:53 Z anton Sprinklers (CEOI24_sprinklers) C++17
100 / 100
 587 ms 8976 KB 
#include<bits/stdc++.h>

using namespace std;

#define int long long
#define pii pair<int, int>

vector<int> flowers;
vector<int> sprinklers;


int last_under(vector<int>& v, int x){
    return (upper_bound(v.begin(), v.end(), x) - v.begin())-1;
}

int first_above(vector<int>& v, int x){
    return lower_bound(v.begin(), v.end(), x) - v.begin();
}


pii get_coverage(pii interval){
    return {first_above(flowers, interval.first), last_under(flowers, interval.second)};
}

bool is_in(pii inter, int pos){
    return (pos>=inter.first && pos<=inter.second);
}

int N, M;

struct DP{
    int val= 0;
    int anc =0;
    string p;
    DP(){};
    DP(int _val, int _anc, string s){
        p = s;
        val = _val;
        anc= _anc;
    }
};

void chmax(DP& a, DP b){
    if(b.val>a.val){
        a= b;
    }
}

vector<DP> solve(int k){
    vector<DP> dp(N+1);

    for(int cur_sprinkler = 0; cur_sprinkler<N; cur_sprinkler++){
        int uncovered_flower = dp[cur_sprinkler].val;
        pii before_inter = get_coverage({sprinklers[cur_sprinkler]-k, sprinklers[cur_sprinkler]});
        if(is_in(before_inter, uncovered_flower)){
            chmax(dp[cur_sprinkler+1], DP(before_inter.second+1, cur_sprinkler, string("L")));
        }
        before_inter = get_coverage({sprinklers[cur_sprinkler], sprinklers[cur_sprinkler]+k});
        if(is_in(before_inter, uncovered_flower)){
            chmax(dp[cur_sprinkler+1], DP(before_inter.second+1, cur_sprinkler, string("R")));
        }

        if(cur_sprinkler<N-1){
            if(sprinklers[cur_sprinkler+1]-sprinklers[cur_sprinkler]<k){
                pii interval = {sprinklers[cur_sprinkler+1]-k, sprinklers[cur_sprinkler]+k};
                if(is_in(get_coverage(interval), uncovered_flower)){
                    chmax(dp[cur_sprinkler+2], DP(before_inter.second+1, cur_sprinkler, string("LR")));

                }
            }
        }

        chmax(dp[cur_sprinkler+1], DP(uncovered_flower, cur_sprinkler, string("R")));

    }

    return dp;
}

string res;
void backtrack(vector<DP>& dp, int pos){
    bool ok = true;
    while(ok){
        res.append(dp[pos].p.begin(), dp[pos].p.end());
        pos= dp[pos].anc;
        ok = pos>0;
    }
}
signed main(){
    cin>>N>>M;
    sprinklers.resize(N);

    for(int i = 0; i<N; i++){
        cin>>sprinklers[i];
    }

    int k;
    flowers.push_back(sprinklers[0]);
    for(int i = 0; i<M; i++){
        cin>>k;
        flowers.push_back(k);
    }

    flowers.push_back(sprinklers.back());


    sort(flowers.begin(), flowers.end());
    int K=1e9;

    if(solve(K).back().val != M+2){
        cout<<-1<<endl;
        return 0;
    }

    for(int step = (1<<30); step>=1; step/=2){
        if(K-step>=0 && solve(K-step).back().val == M+2){
            K-=step;
        }
    }

    cout<<K<<endl;
    auto res_dp = solve(K);
    backtrack(res_dp, N);

    reverse(res.begin(), res.end());

    cout<<res<<endl;
}

Subtask #0
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Correct
2 Correct 0 ms 348 KB Correct

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Correct
2 Correct 23 ms 1444 KB Correct
3 Correct 0 ms 348 KB Correct
4 Correct 27 ms 1488 KB Correct
5 Correct 27 ms 1492 KB Correct
6 Correct 0 ms 348 KB Correct
7 Correct 0 ms 348 KB Correct
8 Correct 6 ms 752 KB Correct
9 Correct 0 ms 344 KB Correct

Subtask #2
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Correct
2 Correct 30 ms 1520 KB Correct
3 Correct 41 ms 904 KB Correct
4 Correct 492 ms 6948 KB Correct
5 Correct 500 ms 7020 KB Correct
6 Correct 1 ms 348 KB Correct
7 Correct 0 ms 348 KB Correct
8 Correct 319 ms 6948 KB Correct
9 Correct 340 ms 7020 KB Correct
10 Correct 365 ms 7016 KB Correct
11 Correct 156 ms 6132 KB Correct
12 Correct 231 ms 3268 KB Correct
13 Correct 326 ms 6680 KB Correct
14 Correct 345 ms 6516 KB Correct
15 Correct 363 ms 6688 KB Correct
16 Correct 315 ms 6508 KB Correct

Subtask #3
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Correct
2 Correct 0 ms 348 KB Correct
3 Correct 1 ms 344 KB Correct
4 Correct 1 ms 348 KB Correct
5 Correct 1 ms 348 KB Correct
6 Correct 1 ms 348 KB Correct
7 Correct 0 ms 348 KB Correct
8 Correct 1 ms 348 KB Correct
9 Correct 0 ms 348 KB Correct
10 Correct 1 ms 348 KB Correct
11 Correct 0 ms 348 KB Correct
12 Correct 1 ms 348 KB Correct
13 Correct 1 ms 348 KB Correct
14 Correct 0 ms 348 KB Correct
15 Correct 1 ms 348 KB Correct
16 Correct 0 ms 348 KB Correct
17 Correct 0 ms 348 KB Correct
18 Correct 0 ms 596 KB Correct
19 Correct 1 ms 348 KB Correct
20 Correct 0 ms 348 KB Correct

Subtask #4
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Correct
2 Correct 85 ms 1608 KB Correct
3 Correct 427 ms 6768 KB Correct
4 Correct 420 ms 8808 KB Correct
5 Correct 425 ms 8784 KB Correct
6 Correct 443 ms 8812 KB Correct
7 Correct 423 ms 8880 KB Correct
8 Correct 427 ms 8908 KB Correct
9 Correct 421 ms 8884 KB Correct
10 Correct 425 ms 8816 KB Correct
11 Correct 429 ms 8816 KB Correct
12 Correct 0 ms 344 KB Correct
13 Correct 0 ms 348 KB Correct
14 Correct 96 ms 7128 KB Correct
15 Correct 164 ms 6964 KB Correct
16 Correct 155 ms 7160 KB Correct
17 Correct 229 ms 7380 KB Correct
18 Correct 258 ms 7532 KB Correct
19 Correct 283 ms 7808 KB Correct
20 Correct 403 ms 8492 KB Correct
21 Correct 413 ms 8560 KB Correct
22 Correct 417 ms 8304 KB Correct
23 Correct 449 ms 8304 KB Correct
24 Correct 441 ms 8092 KB Correct
25 Correct 433 ms 8304 KB Correct
26 Correct 185 ms 6044 KB Correct
27 Correct 156 ms 3540 KB Correct
28 Correct 398 ms 7756 KB Correct
29 Correct 358 ms 7532 KB Correct
30 Correct 388 ms 7760 KB Correct
31 Correct 376 ms 7252 KB Correct

Subtask #5
47.0 / 47.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Correct
2 Correct 0 ms 348 KB Correct
3 Correct 23 ms 1444 KB Correct
4 Correct 0 ms 348 KB Correct
5 Correct 27 ms 1488 KB Correct
6 Correct 27 ms 1492 KB Correct
7 Correct 0 ms 348 KB Correct
8 Correct 0 ms 348 KB Correct
9 Correct 6 ms 752 KB Correct
10 Correct 0 ms 344 KB Correct
11 Correct 30 ms 1520 KB Correct
12 Correct 41 ms 904 KB Correct
13 Correct 492 ms 6948 KB Correct
14 Correct 500 ms 7020 KB Correct
15 Correct 1 ms 348 KB Correct
16 Correct 0 ms 348 KB Correct
17 Correct 319 ms 6948 KB Correct
18 Correct 340 ms 7020 KB Correct
19 Correct 365 ms 7016 KB Correct
20 Correct 156 ms 6132 KB Correct
21 Correct 231 ms 3268 KB Correct
22 Correct 326 ms 6680 KB Correct
23 Correct 345 ms 6516 KB Correct
24 Correct 363 ms 6688 KB Correct
25 Correct 315 ms 6508 KB Correct
26 Correct 1 ms 344 KB Correct
27 Correct 1 ms 348 KB Correct
28 Correct 1 ms 348 KB Correct
29 Correct 1 ms 348 KB Correct
30 Correct 0 ms 348 KB Correct
31 Correct 1 ms 348 KB Correct
32 Correct 0 ms 348 KB Correct
33 Correct 1 ms 348 KB Correct
34 Correct 0 ms 348 KB Correct
35 Correct 1 ms 348 KB Correct
36 Correct 1 ms 348 KB Correct
37 Correct 0 ms 348 KB Correct
38 Correct 1 ms 348 KB Correct
39 Correct 0 ms 348 KB Correct
40 Correct 0 ms 348 KB Correct
41 Correct 0 ms 596 KB Correct
42 Correct 1 ms 348 KB Correct
43 Correct 0 ms 348 KB Correct
44 Correct 85 ms 1608 KB Correct
45 Correct 427 ms 6768 KB Correct
46 Correct 420 ms 8808 KB Correct
47 Correct 425 ms 8784 KB Correct
48 Correct 443 ms 8812 KB Correct
49 Correct 423 ms 8880 KB Correct
50 Correct 427 ms 8908 KB Correct
51 Correct 421 ms 8884 KB Correct
52 Correct 425 ms 8816 KB Correct
53 Correct 429 ms 8816 KB Correct
54 Correct 0 ms 344 KB Correct
55 Correct 0 ms 348 KB Correct
56 Correct 96 ms 7128 KB Correct
57 Correct 164 ms 6964 KB Correct
58 Correct 155 ms 7160 KB Correct
59 Correct 229 ms 7380 KB Correct
60 Correct 258 ms 7532 KB Correct
61 Correct 283 ms 7808 KB Correct
62 Correct 403 ms 8492 KB Correct
63 Correct 413 ms 8560 KB Correct
64 Correct 417 ms 8304 KB Correct
65 Correct 449 ms 8304 KB Correct
66 Correct 441 ms 8092 KB Correct
67 Correct 433 ms 8304 KB Correct
68 Correct 185 ms 6044 KB Correct
69 Correct 156 ms 3540 KB Correct
70 Correct 398 ms 7756 KB Correct
71 Correct 358 ms 7532 KB Correct
72 Correct 388 ms 7760 KB Correct
73 Correct 376 ms 7252 KB Correct
74 Correct 39 ms 2260 KB Correct
75 Correct 587 ms 8888 KB Correct
76 Correct 574 ms 8808 KB Correct
77 Correct 0 ms 348 KB Correct
78 Correct 329 ms 8976 KB Correct
79 Correct 347 ms 8808 KB Correct
80 Correct 394 ms 8808 KB Correct
81 Correct 155 ms 7128 KB Correct
82 Correct 207 ms 7160 KB Correct
83 Correct 195 ms 7164 KB Correct
84 Correct 61 ms 1496 KB Correct
85 Correct 400 ms 7976 KB Correct
86 Correct 419 ms 8132 KB Correct
87 Correct 380 ms 6980 KB Correct
88 Correct 26 ms 2260 KB Correct
89 Correct 29 ms 2252 KB Correct