oj.uz

Submission #155065

# Submission time Handle Problem Language Result Execution time Memory
155065 2019-09-26T05:24:11 Z Charis02 Homecoming (BOI18_homecoming) C++14
100 / 100
 232 ms 116740 KB 
#include<iostream>
#define ll long long
#define rep(i,a,b) for(int i = a;i < b;i++)
#define N 2000003
#define INF 1e16

using namespace std;

ll books[N],prize[N],sum[N],n,k;
ll dp[N][2];
const ll PASSED=1,NPASSED=0;

ll get_sum(ll i,ll j)
{
    if(i == 0)
        return sum[j];

    return sum[j] - sum[i-1];
}

ll solve(int NN,int K,int A[],int B[])
{
    n = NN;
    k = K;
    rep(i,0,n)
    {
        prize[i] = A[i];
        books[i] = B[i];

        if(i == 0)
            sum[i] = books[i];
        else
            sum[i] = sum[i-1]+books[i];
    }

    /*
        if you pass class i and class j and j-i < k it is optimal to pass all classes in between.
    */

    // fix that class 0 is passed

    dp[0][PASSED] = prize[0] - get_sum(0,k-1);
    dp[0][NPASSED] = -INF;

    rep(i,1,n)
    {
        ll nextbook = i+k-1;

        // passed previous class
        ll cur = dp[i-1][PASSED];
        if(nextbook < n)
            cur -= books[nextbook];
        cur+=prize[i];
        dp[i][PASSED] = cur;

        //didn't pass previous class
        cur = dp[i-1][NPASSED];
        cur -= get_sum(i,min(n-1,nextbook)); // if we add stuff that is already in dp[i-1][NPASSED], then optimal answer isn't here since we could just pass class i-1
        cur+=prize[i];
        dp[i][PASSED] = max(dp[i][PASSED],cur);

        dp[i][NPASSED] = max(dp[i-1][NPASSED],dp[i-1][PASSED]);
    }

    ll ans = max(dp[n-1][PASSED],dp[n-1][NPASSED]);

    // fix that he didn't pass class 0

    dp[0][NPASSED] = 0;
    dp[0][PASSED] = -INF;

    rep(i,1,n)
    {
        ll nextbook = (i+k-1)%n;

        // passed previous class
        ll cur = dp[i-1][PASSED];
        cur -= books[nextbook];
        cur+=prize[i];
        dp[i][PASSED] = cur;

        //didn't pass previous class
        cur = dp[i-1][NPASSED];
        if(nextbook < i)
            cur -= get_sum(i,n-1) + get_sum(0,nextbook);
        else
            cur -= get_sum(i,nextbook);

        cur+=prize[i];
        dp[i][PASSED] = max(dp[i][PASSED],cur);

        dp[i][NPASSED] = max(dp[i-1][NPASSED],dp[i-1][PASSED]);
    }

    ans = max(ans,dp[n-1][PASSED]);
    ans = max(ans,dp[n-1][NPASSED]);

    return ans;
}

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct

Subtask #2
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 3 ms 636 KB Output is correct
7 Correct 3 ms 636 KB Output is correct
8 Correct 3 ms 632 KB Output is correct
9 Correct 3 ms 636 KB Output is correct
10 Correct 3 ms 504 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 27816 KB Output is correct
2 Correct 5 ms 1016 KB Output is correct
3 Correct 231 ms 100916 KB Output is correct
4 Correct 4 ms 1588 KB Output is correct
5 Correct 12 ms 3536 KB Output is correct

Subtask #4
38.0 / 38.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 3 ms 636 KB Output is correct
7 Correct 3 ms 636 KB Output is correct
8 Correct 3 ms 632 KB Output is correct
9 Correct 3 ms 636 KB Output is correct
10 Correct 3 ms 504 KB Output is correct
11 Correct 60 ms 27816 KB Output is correct
12 Correct 5 ms 1016 KB Output is correct
13 Correct 231 ms 100916 KB Output is correct
14 Correct 4 ms 1588 KB Output is correct
15 Correct 12 ms 3536 KB Output is correct
16 Correct 232 ms 100928 KB Output is correct
17 Correct 95 ms 15352 KB Output is correct
18 Correct 168 ms 11952 KB Output is correct
19 Correct 171 ms 74604 KB Output is correct
20 Correct 184 ms 116740 KB Output is correct
21 Correct 166 ms 72160 KB Output is correct