Submission #1298714

#	Time	Username	Problem	Language	Result	Execution time	Memory
1298714		tdkhai	Feast (NOI19_feast)	C++20	0 / 100	57 ms	10840 KiB

feast

/*
        _.-- ,.--.
      .'   .'     /
       @       |'..--------._
     /      \._/              '.
    /  .-.-                     \
   (  /    \                     \
   \\      '.                  | #
    \\       \   -.           /
     :\       |    )._____.'   \
      "       |   /  \  |  \    )
              |   |./'  :__ \.-'
              '--'
*/
#include<bits/stdc++.h>
#define ll long long
#define llll pair<ll,ll>
#define ii pair<int,int>
#define fi first
#define se second
#define FOR(i,l,r) for(int i=l;i<=r;i++)
#define FOD(i,r,l) for(int i=r;i>=l;i--)
#define ull unsigned long long
#define iii pair<int,ii>
#define iv pair<pii,ii>
#define db double
#define ld long double
#define pb push_back
#define tdk "kfph"


using namespace std;

const int dx[]  = {1, -1, 0, 0};
const int dy[]  = {0, 0, -1, 1};
const int dxx[] = {1, 1, -1, -1, 2, 2, -2, -2};
const int dyy[] = {2, -2, 2, -2, 1, -1, 1, -1};
const ll INF=1e18;

const int N= 3e5+5;
int a[N],n,k;
pair<ll,int> dp[N][2];

pair<ll,int> check(int x)
{
    dp[0][1].fi=-x;
    dp[0][1].se=1;
    for(int i=1;i<=n;i++)
    {
        dp[i][0]=max(dp[i-1][0],dp[i-1][1]);
        dp[i][1]=max(make_pair(dp[i-1][1].fi+a[i],dp[i-1][1].se),make_pair(dp[i-1][0].fi+a[i]-x,dp[i-1][0].se+1));
    }
    return max(dp[n][0],dp[n][1]);
}
void kfph()
{
    cin >> n >> k;
    for(int i=1;i<=n;i++)
    {
        cin >> a[i];
    }
    int l=1,r=*max_element(a+1,a+1+n),ans=1;
    while(l<=r)
    {
        int mid=l+r>>1;
        if(check(mid).se>=k)
        {
            ans=mid;
            r=mid-1;
        }
        else
        {
            l=mid+1;
        }
    }
    cout << check(ans).fi+k*ans;
}
int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    if(fopen(tdk".inp","r"))
    {
        freopen(tdk".inp","r",stdin);
        freopen(tdk".out","w",stdout);
    }
    int t=1;
    //cin >> t;
    while(t--)
    {
        kfph();
    }
    return 0;
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:83:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         freopen(tdk".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
feast.cpp:84:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         freopen(tdk".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 18
• Subtask 4: 0 / 10
• Subtask 5: 0 / 11
• Subtask 6: 0 / 20
• Subtask 7: 0 / 29