oj.uz

Submission #1103139

# Submission time Handle Problem Language Result Execution time Memory
1103139 2024-10-20T09:13:43 Z DuongKiet Feast (NOI19_feast) C++17
30 / 100
 31 ms 3068 KB 
#include <bits/stdc++.h>
#define N 300005
#define inf 100000000000000000LL
#define ll long long
#define int long long
#define ii pair <int,long long>
#define fi first
#define se second
#define all(x) x.begin(),x.end()
#define pb push_back

using namespace std;

const unsigned ll Mod = 1000000007LL;

int n, k, a[N];
void init(){

    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        cin >> a[i];
}
bool ifsub1(){

    for (int i = 1; i <= n; i++)
        if (a[i] < 0) return 0;
    return 1;
}
void sub1(){

    int ans = 0;
    for (int i = 1; i <= n; i++)
        ans += a[i];
    cout << ans << '\n';
}
int pos;
bool ifsub2(){

    int cnt = 0;
    for (int i = 1; i <= n; i++)
        if (a[i] < 0) {pos = a[i]; cnt++;}
    return (cnt < 2);
}
void sub2(){

    int sum = 0, suml = 0, am = 0;
    bool kt = 0;
    for (int i = 1; i <= n; i++){
        if (a[i] < 0) {
            kt = 1;
            am = a[i];
        }
        if (!kt) suml += a[i];
        sum += a[i];
    }
    if (k > 1)
        cout << sum - am << '\n';
    else cout << max(suml, max(sum, sum - suml - am));
}
void sub3(){
    int ans = 0, res = 0;
    for (int i = 1; i <= n; i++) {
        res = max(0ll, res + a[i]);
        ans = max(ans, res);
    }
    cout << ans << '\n';
}
//int pa[N], sz[N];
//int findpa(int u){
//
//    if (u == pa[u]) return u;
//    return pa[u] = findpa(pa[u]);
//}
//void Union(int a, int b){
//
//    a = findpa(a);
//    b = findpa(b);
//    if (a == b) return;
//    if (sz[a] < sz[b]) swap(a,b);
//    pa[b] = a;
//    sz[a] += sz[b];
//    sum[a] += sum[b];
//}
//vector <ii> d;
//void Add(int u){
//    d.pb({u, sum[u]});
//}
//void sub6(){
//    for (int i = 1; i <= n; i++){
//        pa[i] = i;
//        sz[i] = 1;
//        sum[i] = a[i];
//    }
//    int parduong, param;
//    bool task = 0;
//    if (a[1] >= 0) {parduong = 1; task = 1;}
//    else param = 1;
//    for (int i = 1; i <= n; i++){
//        if (a[i] >= 0) {
//            if (task)
//                Union(parduong, i);
//            else parduong = i;
//            task = 1;
//        }
//        else {
//            if (!task) Union(param, i);
//            else param = i;
//            task = 0;
//        }
//    }
//    int curpa = findpa(1);
//    Add(curpa);
//    for (int i = 1; i <= n; i++){
//        int u = findpa(i);
//        if (u != curpa){
//            curpa = u;
//            Add(u);
//        }
//    }
//    for (int i = 2; i < d.size(); i++){
//        if (d[i].se > 0 && d[i-2].se > 0){
//            g.pb({d[i].fi, d[i - 2].fi, d[i].se + d[i].se });
//        }
//    }
//}
pair<long double, int> dp[N + 1][2];

bool check(long double res) {
	dp[0][0] = {0, 0}, dp[0][1] = {-inf, 0};
	for (int i = 1; i <= n; ++i) {
		dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]);
		dp[i][1] =
		    max(make_pair(dp[i - 1][1].first + a[i], dp[i - 1][1].second),
		        make_pair(dp[i - 1][0].first + a[i] - res, dp[i - 1][0].second + 1));
	}
	return max(dp[n][0], dp[n][1]).second >= k;
};
void solve(){

    int lower = 0, upper = inf;
	while (lower + 1 < upper) {
		int mid = (lower + upper) / 2;
		if (check(mid)) {
			lower = mid;
		} else {
			upper = mid;
		}
	}
	int res = lower;
	check(res);
	cout << res * k + max(dp[n][0].first, dp[n][1].first);
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    #define nametask "PRESUFF"
    if(fopen(nametask".inp", "r")) {
        freopen(nametask".inp", "r", stdin);
        freopen(nametask".out", "w", stdout);
    }
    init();
    if (ifsub1()) return sub1(), 0;
    if (ifsub2()) return sub2(), 0;
    if (k == 1) return sub3(), 0;
//    if (k <= n && n <= 2000) return sub6(), 0;
    solve();
    return 0;
}
/// Duong Anh Kiet from Kien Giang ///
/*
6 1
-1 -2 -1 2 -1 2
*/

Compilation message

feast.cpp: In function 'int main()':
feast.cpp:159:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  159 |         freopen(nametask".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
feast.cpp:160:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  160 |         freopen(nametask".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 2640 KB Output is correct
2 Correct 20 ms 2908 KB Output is correct
3 Correct 20 ms 2780 KB Output is correct
4 Correct 20 ms 2896 KB Output is correct
5 Correct 20 ms 2896 KB Output is correct
6 Correct 19 ms 2776 KB Output is correct
7 Correct 19 ms 2640 KB Output is correct
8 Correct 25 ms 2896 KB Output is correct
9 Correct 19 ms 2780 KB Output is correct
10 Correct 21 ms 2776 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 2776 KB Output is correct
2 Correct 14 ms 2896 KB Output is correct
3 Correct 16 ms 2896 KB Output is correct
4 Correct 15 ms 2784 KB Output is correct
5 Correct 21 ms 2640 KB Output is correct
6 Correct 15 ms 2912 KB Output is correct
7 Correct 18 ms 2896 KB Output is correct
8 Correct 23 ms 2920 KB Output is correct
9 Correct 20 ms 2640 KB Output is correct
10 Correct 13 ms 2896 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 2896 KB Output is correct
2 Correct 23 ms 2888 KB Output is correct
3 Correct 26 ms 2792 KB Output is correct
4 Correct 25 ms 2908 KB Output is correct
5 Correct 31 ms 2900 KB Output is correct
6 Correct 24 ms 2912 KB Output is correct
7 Correct 23 ms 2896 KB Output is correct
8 Correct 23 ms 2896 KB Output is correct
9 Correct 25 ms 3068 KB Output is correct
10 Correct 25 ms 2776 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2384 KB Output is correct
2 Incorrect 1 ms 2384 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2384 KB Output is correct
2 Incorrect 1 ms 2384 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2384 KB Output is correct
2 Incorrect 1 ms 2384 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 2640 KB Output is correct
2 Correct 20 ms 2908 KB Output is correct
3 Correct 20 ms 2780 KB Output is correct
4 Correct 20 ms 2896 KB Output is correct
5 Correct 20 ms 2896 KB Output is correct
6 Correct 19 ms 2776 KB Output is correct
7 Correct 19 ms 2640 KB Output is correct
8 Correct 25 ms 2896 KB Output is correct
9 Correct 19 ms 2780 KB Output is correct
10 Correct 21 ms 2776 KB Output is correct
11 Correct 13 ms 2776 KB Output is correct
12 Correct 14 ms 2896 KB Output is correct
13 Correct 16 ms 2896 KB Output is correct
14 Correct 15 ms 2784 KB Output is correct
15 Correct 21 ms 2640 KB Output is correct
16 Correct 15 ms 2912 KB Output is correct
17 Correct 18 ms 2896 KB Output is correct
18 Correct 23 ms 2920 KB Output is correct
19 Correct 20 ms 2640 KB Output is correct
20 Correct 13 ms 2896 KB Output is correct
21 Correct 26 ms 2896 KB Output is correct
22 Correct 23 ms 2888 KB Output is correct
23 Correct 26 ms 2792 KB Output is correct
24 Correct 25 ms 2908 KB Output is correct
25 Correct 31 ms 2900 KB Output is correct
26 Correct 24 ms 2912 KB Output is correct
27 Correct 23 ms 2896 KB Output is correct
28 Correct 23 ms 2896 KB Output is correct
29 Correct 25 ms 3068 KB Output is correct
30 Correct 25 ms 2776 KB Output is correct
31 Correct 1 ms 2384 KB Output is correct
32 Incorrect 1 ms 2384 KB Output isn't correct
33 Halted 0 ms 0 KB -