Submission #117084

#	Time	Username	Problem	Language	Result	Execution time	Memory
117084		Bruteforceman	Homecoming (BOI18_homecoming)	C++11	100 / 100	204 ms	102512 KiB

homecoming

#include "bits/stdc++.h"
#include "homecoming.h"
using namespace std;
const long long inf = 1e17;
long long S[2000010];
long long dp[2][2000010];

long long solve(int N, int K, int *A, int *B) {
	long long all = 0;
	for(int i = 0; i < N; i++) {
		all += A[i] - B[i];
	}
	long long ans = all;

	long long sum = 0;
	for(int i = 0; i < K; i++) {
		sum += B[i];
	}
	for(int i = 0; i < N; i++) {
		S[i] = sum;
		sum += B[(i + K) % N] - B[i];
	}
	dp[0][0] = 0;
	dp[1][0] = -inf;
	for(int j = 1; j < N; j++) {
		int id = j;
		int prev = (id + N - 1) % N;
		dp[0][id] = max(dp[0][prev], dp[1][prev]);
		dp[1][id] = max(dp[0][prev] + A[id] - S[id], dp[1][prev] + A[id] - B[(id + K - 1) % N]);
	}
	ans = max(ans, dp[0][N - 1]);
	ans = max(ans, dp[1][N - 1]);
	
	dp[0][0] = -inf;
	dp[1][0] = A[0] - S[0];
	for(int j = 1; j < N; j++) {
		int id = j;
		int prev = (id + N - 1) % N;
		dp[0][id] = max(dp[0][prev], dp[1][prev]);
		dp[1][id] = max(dp[0][prev] + A[id] - S[id], dp[1][prev] + A[id] - B[(id + K - 1) % N]);
	}
	ans = max(ans, dp[0][N - 1]);

	dp[0][0] = -inf;
	dp[1][0] = A[0] - B[K - 1];
	for(int j = 1; j < N; j++) {
		int id = j;
		int prev = (id + N - 1) % N;
		dp[0][id] = max(dp[0][prev], dp[1][prev]);
		dp[1][id] = max(dp[0][prev] + A[id] - S[id], dp[1][prev] + A[id] - B[(id + K - 1) % N]);
	}	
	ans = max(ans, dp[1][N - 1]);
	return ans;
}

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