Submission #1025666

#	Time	Username	Problem	Language	Result	Execution time	Memory
1025666		ach00	Feast (NOI19_feast)	C++14	0 / 100	1038 ms	40288 KiB

feast

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int n,k; 
vector<ll> W;
vector<vector<ll>> dp(2, vector<ll>(300005, -1));
vector<vector<ll>> dpcnt(2, vector<ll>(300005, -1));
ll pen;
ll solve(bool w, int i) {
    if(dp[w][i] != -1) return dp[w][i];
    if(i >= n) return 0;
    ll ans = numeric_limits<int>::min();
    if(w == false) {
        if(solve(false, i+1) > ans) {
            dpcnt[w][i] = dpcnt[w][i+1];
            ans = solve(false, i+1);
        }
        if(-pen + solve(true, i+1) > ans) {
            dpcnt[w][i] = 1 + dpcnt[w][i+1]; 
            ans = -pen + solve(true, i+1);
        }
    } else {
        if(W[i] + solve(false, i+1) > ans) {
            dpcnt[w][i] = dpcnt[w][i+1];
            ans = W[i] + solve(false, i+1);
        }
        if(W[i] + solve(true, i+1) > ans) {
            dpcnt[w][i] = dpcnt[w][i+1];
            ans = W[i] + solve(true, i+1); 
        }
    }
    dp[w][i] = ans;
    return ans;
}


int main() {
    cin >> n >> k;
    W.resize(n);
    for(int i = 0; i < n; i++) {
        cin >> W[i];
    }
    pen = 0;

    ll lower = 0;
    ll upper = numeric_limits<ll>::max();
    while(lower < upper) {
        ll mid = (lower + upper)/2;
        pen = mid;
        dp = vector<vector<ll>>(2, vector<ll>(300005, -1));
        dpcnt = vector<vector<ll>>(2, vector<ll>(300005, -1));
        ll start = solve(true, 0); ll dstart = solve(false, 0);
        if(start >= dstart) {
            int cnt = dpcnt[true][0];
            if(cnt > k) {
                lower = mid;
            } else {
                upper = mid;
            }
        } else {
            int cnt = dpcnt[true][0];
            if(cnt > k) {
                lower = mid;
            } else {
                upper = mid;
            }
        }
    }
    pen = lower;
    ll start = solve(true, 0); ll dstart = solve(false, 0);
    ll cnt;
    if(start >= dstart) cnt = dpcnt[true][0];
    else cnt = dpcnt[false][0];
    cout << max(start, dstart) + cnt*pen;
}

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