Submission #1123498

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123498		pndhpndh	Stove (JOI18_stove)	C++20	0 / 100	1 ms	324 KiB

stove

#include<bits/stdc++.h>
#define int long long
#define pb push_back
#define task "task"
using namespace std;
const int inf = 1e18;
const int mx = 2e5 + 5;
int n, k;
double a[mx];
pair<double,int> dp[mx];
void read(){
    cin >> n >> k;
    for (int i = 1; i <= n; i++){
        cin >> a[i];
    }
}

void solve(){
    double l = 0, r = inf;
    double ans;
    for (int t = 1; t <= 1000; t++){
        double mid = (l + r)/2;
        for (int i = 1; i <= n; i++){
            dp[i] = {0, 0};
        }
        dp[1] = {1, 1};
        for (int i = 2; i <= n; i++){
            dp[i] = min(make_pair(dp[i - 1].first + 1.0 + mid, dp[i - 1].second + 1), make_pair(dp[i - 1].first + a[i] - a[i - 1], dp[i - 1].second));
        }
        if (dp[n].second <= k){
            ans = dp[n].first - mid * (dp[n].second - 1);
//            cout << dp[n].first << " " << dp[n].second << " " << mid << " " << l << " " << r << " " << ans << '\n';
            r = mid;
        }else{
            l = mid;
        }
    }
    cout << ans;
}
signed main(){
    cin.tie(0)->sync_with_stdio(0);
    if(fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    read();
    solve();
}

Compilation message (stderr)

stove.cpp: In function 'int main()':
stove.cpp:43:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
stove.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 20
• Subtask 2: 0 / 30
• Subtask 3: 0 / 50