Submission #254189

#	Time	Username	Problem	Language	Result	Execution time	Memory
254189		shayan_p	Homecoming (BOI18_homecoming)	C++14	100 / 100	189 ms	118140 KiB

homecoming

// And you curse yourself for things you never done

#include<bits/stdc++.h>

#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;

const int maxn = 2e6 + 10, mod = 1e9 + 7;
const ll inf = 1e18;

int a[maxn], b[maxn];
ll dp[maxn][2], A[maxn], B[maxn];

ll solve(int n, int k, int *a, int *b){
    for(int i = 0; i < n; i++)
	A[i] = a[i] - b[i];
    ll sm = 0;
    for(int i = 1; i <= k-1; i++)
	sm+= a[n-i];
    for(int i = 0; i < n; i++)
	B[i] = -sm, sm+= a[i], sm-= a[(i + n - k + 1) % n];
    ll ans = 0;
    for(int w = 0; w < 2; w++){
	if(w == 0)
	    dp[0][0] = 0, dp[0][1] = -inf;
	else
	    dp[0][0] = -inf, dp[0][1] = A[0];
	for(int i = 1; i < n; i++){
	    dp[i][1] = max(dp[i-1][1], dp[i-1][0]) + A[i];
	    dp[i][0] = max(dp[i-1][0], dp[i-1][1] + B[i]);
	}
	for(int w2 = 0; w2 < 2; w2++)
	    ans = max(ans, dp[n-1][w2] + ((w2 == 1 && w == 0) ? B[0] : 0));
    }
    return ans;
}

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