Submission #843606

#	Time	Username	Problem	Language	Result	Execution time	Memory
843606		fanwen	Feast (NOI19_feast)	C++17	100 / 100	123 ms	9716 KiB

feast

#include <bits/stdc++.h>

using namespace std;

#define MASK(x) (1LL << (x))
#define BIT(x, i) (((x) >> (i)) & 1)
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for (int i = 0, _n = n; i < _n; ++i)
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define FORE(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define debug(...) "[" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }

template <class A, class B> bool minimize(A &a, B b)  { if (a > b) { a = b; return true; } return false; }
template <class A, class B> bool maximize(A &a, B b)  { if (a < b) { a = b; return true; } return false; }

const int MAXN = 3e5 + 5;

int N, K, cnt[MAXN];
long long a[MAXN], dp[MAXN];

bool check(long long val) {
	pair <long long, int> best(0, 0);
	FOR(i, 1, N) {
		dp[i] = dp[i - 1], cnt[i] = cnt[i - 1];
		if(maximize(dp[i], best.first + a[i] - val)) {
			cnt[i] = cnt[best.second] + 1;
		}

		if(maximize(best.first, dp[i] - a[i])) {
			best.second = i;
		}
	}
	return cnt[N] <= K;
}

void you_make_it(void) {

    cin >> N >> K;
    FOR(i, 1, N) cin >> a[i], a[i] += a[i - 1];
    long long L = -1, R = 1E18;
    while(R - L > 1) {
    	auto Mid = L + R >> 1LL;
    	if(check(Mid)) R = Mid;
    	else L = Mid;
    }
    check(R);
    cout << dp[N] + 1LL * cnt[N] * R;
}

signed main() {

#ifdef LOCAL
    freopen("TASK.inp", "r", stdin);
    freopen("TASK.out", "w", stdout);
#endif
    auto start_time = chrono::steady_clock::now();

    cin.tie(0), cout.tie(0) -> sync_with_stdio(0);

    you_make_it();

    auto end_time = chrono::steady_clock::now();

    cerr << "\nExecution time : " << chrono::duration_cast <chrono::milliseconds> (end_time - start_time).count() << "[ms]" << endl;

    return (0 ^ 0);
}

// Dream it. Wish it. Do it.

Compilation message (stderr)

feast.cpp: In function 'void you_make_it()':
feast.cpp:44:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   44 |      auto Mid = L + R >> 1LL;
      |                 ~~^~~

• 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