Submission #866523

#	Time	Username	Problem	Language	Result	Execution time	Memory
866523		farica	Homecoming (BOI18_homecoming)	C++14	0 / 100	32 ms	23896 KiB

homecoming

#include <bits/stdc++.h>
#include "homecoming.h"

using namespace std;

const int MAX_N=2000000;
const int N=1000001;

long long int solve(int N, int K, int *A, int *B) {
    int n=N, k=K;
    cin >> n >> k;
    long long a[n], b[n], pref[n];
    for(int i=0; i<n; ++i) a[i] = A[i];
    for(int i=0; i<n; ++i) {
        b[i] = B[i];
        pref[i] = b[i];
        if(i) pref[i] += pref[i-1];
    }
    long long dp[n][2], ans=0;
    dp[0][0] = -1e18;
    dp[0][1] = a[0] - pref[k-1];
    for(int i=1; i<n; ++i) {
        dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
        long long val1 = dp[i-1][1] + a[i];
        if((i+k-1)<n) val1 -= b[i+k-1];
        long long val2 = dp[i-1][0] + a[i] - pref[min(i+k-1, n-1)] + pref[i-1];
        dp[i][1] = max(val1,val2);
    }
    ans = max(ans, dp[n-1][1]);
    ans = max(ans, dp[n-1][0]);
    dp[0][1] = -1e18;
    dp[0][0] = 0;
    for(int i=1; i<n; ++i) {
        dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
        long long val1 = dp[i-1][1] + a[i] - b[(i+k-1)%n];
        long long val2 = dp[i-1][0] + a[i];
        if((i+k-1)<n) val2 -= pref[i+k-1] - pref[i-1];
        else val2 -= pref[n-1] - pref[i-1] + pref[(i+k-1)%n];
        dp[i][1] = max(val1, val2);
    }
    ans = max(ans, dp[n-1][0]);
    return max(ans, dp[n-1][1]);
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 18
• Subtask 3: 0 / 31
• Subtask 4: 0 / 38