Submission #257502

#	Time	Username	Problem	Language	Result	Execution time	Memory
257502		karma	Feast (NOI19_feast)	C++14	30 / 100	144 ms	11000 KiB

feast

#include <bits/stdc++.h>
#define pb          emplace_back
#define ll          long long
#define fi          first
#define se          second
#define mp          make_pair
//#define int         int64_t

using namespace std;

const int N = int(6e5) + 7;
typedef pair<ll, int> pii;

pii f[N][2];
int n, k, a[N];

/// 0 - ok
/// 1 - opening

pii operator - (const pii& a, const ll& x) {
    return pii(a.fi - x, a.se + 1);
}
pii operator + (const pii& a, const ll& x) {
    return pii(a.fi + x, a.se);
}
pii max(const pii& x, const pii& y) {
    if(x.fi == y.fi) return x.se < y.se? x: y;
    return x.fi > y.fi? x: y;
}

pii check(ll mid) {
    f[0][1] = {-mid, 1};
    for(int i = 1; i <= n; ++i) {
        f[i][1] = max(f[i - 1][1], f[i - 1][0] - mid) + a[i];
        f[i][0] = max(f[i - 1][1] + a[i], f[i - 1][0]);
    }
    return max(f[n][0], f[n][1]);
}

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    #define Task        "test"
    if(fopen(Task".inp", "r")) {
        freopen(Task".inp", "r", stdin);
        freopen(Task".out", "w", stdout);
    }
    cin >> n >> k;
    for(int i = 1; i <= n; ++i) cin >> a[i];
    ll low = 0, mid, high = 1ll * n * (int)1e9;
    while(low <= high) {
        mid = (low + high) >> 1;
        if(check(mid).se > k) low = mid + 1;
        else high = mid - 1;
    }
    cout << check(low).fi + 1ll * low * k;
}

Compilation message (stderr)

feast.cpp: In function 'int32_t main()':
feast.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(Task".inp", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:46:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(Task".out", "w", stdout);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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