Submission #1017410

#	Time	Username	Problem	Language	Result	Execution time	Memory
1017410		vjudge1	Feast (NOI19_feast)	C++17	100 / 100	107 ms	12132 KiB

feast

#include<bits/stdc++.h>

using namespace std;
#define int long long
pair<int, int> dp[300005][2];
int n, k, a[300005];
pair<int, int> sigma(int cost) {
    dp[0][1] = {-1e18, 0};
    for (int i = 1; i <= n; i++) {
        dp[i][0] = max(dp[i-1][0], dp[i-1][1]);
        pair<int,int> v1 = {dp[i-1][1].first+a[i],dp[i-1][1].second};
        pair<int,int> v2 = {dp[i-1][0].first+a[i]-cost, dp[i-1][0].second+1};
        dp[i][1] = (v1.first > v2.first ? v1 : v2);
        //if(cost == 2) cout << i << ' ' << dp[i][0].first << ' ' << dp[i][0].second << ' ' << dp[i][1].first << ' ' << dp[i][1].second << '\n';
    }
    return max(dp[n][0], dp[n][1]);
}
void solve() {
    cin >> n >> k;
    for (int i = 1; i <= n; i++) cin >> a[i];
    int l = 0, r = 3e14, mid, ans=0;
    while(l <= r) {
        mid = (l + r) / 2;
        pair<int, int> val = sigma(mid);
        if(val.second <= k) {
           // cout << mid << ' ' << val.first << ' ' << val.second << '\n';
            ans = max(ans, val.first + mid * val.second);
            r = mid-1;
        }
        else l = mid+1;
    }
    cout << ans;
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if(fopen("input.inp","r")){
        freopen("input.inp", "r", stdin);
        freopen("output.out", "w", stdout);
    }
    int t = 1;
    // cin >> t;
    while(t--) {
        solve();
    }
}

Compilation message (stderr)

feast.cpp: In function 'int main()':
feast.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen("input.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:39:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |         freopen("output.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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