Submission #962655

#	Time	Username	Problem	Language	Result	Execution time	Memory
962655		biximo	Feast (NOI19_feast)	C++17	100 / 100	908 ms	23540 KiB

feast

#include <bits/stdc++.h>
#define N 300005
using namespace std;
typedef pair<long double, int> pi;
pi DP[N][2];
int n, k, seq[N];
int doDP(long double pen) {
	for(auto&i: DP) for(auto&j: i) j = make_pair(-9e18,0);
	DP[0][0] = {0,0};
	for(int i = 1; i <= n+1; i ++) {
		DP[i][0] = max(DP[i-1][0], DP[i-1][1]);
		DP[i][1] = max(DP[i-1][1], make_pair(DP[i-1][0].first-pen, DP[i-1][0].second+1));
		DP[i][1].first += seq[i];
	}
	return DP[n+1][0].second;
}
int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> k;
    int pc = 0;
    for(int i = 1; i <= n; i ++) {
    	cin >> seq[i];
    	if(seq[i] > 0 && seq[i-1] <= 0) pc ++;
    }
    k = min(k, pc);
    long double l=0,h=1e13;
    for(int i = 0; i < 100; i ++) {
    	long double m = (l+h)/2;
    	int res = doDP(m);
    	if(res > k) {
    		l = m;
    	} else {
    		h = m;
    	}
    }
    cout << (long long)round(DP[n+1][0].first + k*l);
}

• 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