Submission #1088334

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088334		vjudge1	Discharging (NOI20_discharging)	C++17	47 / 100	78 ms	17872 KiB

Discharging

#include<bits/stdc++.h>
#define taskname ""
#define el '\n'
#define fi first
#define sc second
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
#define int long long
using namespace std;
#define Faster ios_base::sync_with_stdio(false);cin.tie(0);
const int maxn=1e6+33;
const int N=1e5;
const int mod=1e9+7;
const long long INF=1e18+2;
int n,cost[1505][1505],a[maxn];
int dp[maxn];
void sub1()
{
    for(int i=1;i<=n;i++)
    {
        cost[i][i]=a[i];
        for(int j=i+1;j<=n;j++)
        {
            cost[i][j]=max(cost[i][j-1],a[j]);
        }
    }
    for(int i=1;i<=n;i++)
    {
        dp[i]=cost[1][i]*n;
        for(int j=1;j<i;j++)
        {
            dp[i]=min(dp[i],dp[j]+cost[j+1][i]*(n-j));
        }
    }
    cout<<dp[n];
}
void sub2()
{
    cout<<a[1]*n;
}
signed main()
{
    if (fopen(taskname".INP","r"))
    {
        freopen(taskname".INP","r",stdin);
        freopen(taskname".OUT","w",stdout);
    }
    Faster
    cin>>n;
    int inc=0,dec=0;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        if(i>1&&a[i]>a[i-1]) inc=1;
        if(i>1&&a[i]<a[i-1]) dec=1;
    }
    if(n<=1500) sub1();
    else if(inc==0) sub2();
}

Compilation message (stderr)

Discharging.cpp: In function 'int main()':
Discharging.cpp:50:15: warning: variable 'dec' set but not used [-Wunused-but-set-variable]
   50 |     int inc=0,dec=0;
      |               ^~~
Discharging.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen(taskname".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Discharging.cpp:46:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |         freopen(taskname".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 0 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 0 / 28