Submission #755280

#	Time	Username	Problem	Language	Result	Execution time	Memory
755280		He_Huanglu	Feast (NOI19_feast)	C++17	100 / 100	313 ms	18628 KiB

feast

#include <bits/stdc++.h>
#define ii pair<long long, int>
#define fi first
#define se second
using namespace std;

const int N = 3e5 + 5;
int n, k, a[N];
long long ans, tax, l, r = 1e18;
ii f[N][3];

main () {
    cin.tie(0)->sync_with_stdio(0);
    if(fopen("task.inp", "r")) {
        freopen("task.inp", "r", stdin);
        freopen("wa.out", "w", stdout);
    }
    cin >> n >> k;
    for(int i = 1; i <= n; i++) cin >> a[i];
    f[1][1].fi = -1e18;
    while (l <= r) {
        tax = (l + r) >> 1;
        f[1][2] = {a[1] - tax, 1};
        for(int i = 2; i <= n; i++) {
            f[i][0] = max({f[i - 1][0], f[i - 1][1], f[i - 1][2]});
            f[i][1] = max(f[i - 1][1], f[i - 1][2]);
            f[i][1].fi += a[i];
            f[i][2] = {f[i][0].fi + a[i] - tax, f[i][0].se + 1};
        }
        ii tmp = max({f[n][0], f[n][1], f[n][2]});
        if(tmp.se <= k) {
            ans = tmp.fi + tax * tmp.se;
            r = tax - 1;
        }
        else l = tax + 1;
    }
    cout << ans;
}

Compilation message (stderr)

feast.cpp:12:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   12 | main () {
      | ^~~~
feast.cpp: In function 'int main()':
feast.cpp:15:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   15 |         freopen("task.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |         freopen("wa.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