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Submission #358630

# Submission time Handle Problem Language Result Execution time Memory
358630 2021-01-26T02:41:09 Z blue Watching (JOI13_watching) C++17
100 / 100
 223 ms 8812 KB 
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int N, P, Q;
vector<int> A;
int moveW[2001], move2W[2001];
int dp[2001][2001]; //maximum index that can be reached with p small cameras and q large cameras

int b_search(int a, int b)
{
    if(a == b) return a;
    int w = (a+b)/2;

    for(int p = 0; p <= P; p++)
    {
        for(int q = 0; q <= Q; q++)
        {
            dp[p][q] = 0;
        }
    }


    int i, j = 0;
    for(i = 0; i < N; i++)
    {
        while(j < N && A[j+1] <= A[i+1] + w - 1) j++;
        moveW[i] = j;
    }
    moveW[N] = N;

    j = 0;
    for(i = 0; i <= N; i++)
    {
        while(j < N && A[j+1] <= A[i+1] + 2*w - 1) j++;
        move2W[i] = j;
    }
    move2W[N] = N;

    for(int p = 0; p <= P; p++)
    {
        for(int q = 0; q <= Q; q++)
        {
            if(p < P)
                dp[p+1][q] = max(dp[p+1][q], moveW[dp[p][q]]);
            if(q < Q)
                dp[p][q+1] = max(dp[p][q+1], move2W[dp[p][q]]);
        }
    }
    if(dp[P][Q] >= N)
        return b_search(a, w);
    else
        return b_search(w+1, b);
}

int main()
{
    cin >> N >> P >> Q;

    A = vector<int>(N+2);
    A[0] = 0;
    for(int i = 1; i <= N; i++) cin >> A[i];
    A[N+1] = 1e9;
    sort(A.begin(), A.end());

    if(P+Q >= N)
    {
        cout << 1 << '\n';
        return 0;
    }

    cout << b_search(1, 5e8) << '\n';
}

Subtask #1
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 1 ms 384 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 640 KB Output is correct
12 Correct 1 ms 492 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct

Subtask #2
50.0 / 50.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 2 ms 364 KB Output is correct
5 Correct 2 ms 364 KB Output is correct
6 Correct 2 ms 364 KB Output is correct
7 Correct 2 ms 364 KB Output is correct
8 Correct 23 ms 1260 KB Output is correct
9 Correct 25 ms 3820 KB Output is correct
10 Correct 47 ms 8812 KB Output is correct
11 Correct 39 ms 1004 KB Output is correct
12 Correct 223 ms 8100 KB Output is correct
13 Correct 2 ms 364 KB Output is correct
14 Correct 2 ms 512 KB Output is correct
15 Correct 2 ms 492 KB Output is correct