Submission #601820

#	Time	Username	Problem	Language	Result	Execution time	Memory
601820		Mazaalai	Meetings (IOI18_meetings)	C++17	19 / 100	416 ms	196316 KiB

meetings

#include "meetings.h"
#include <bits/stdc++.h>
#define sz(x) (int)x.size()
#define ALL(x) x.begin(), x.end()
#define chmax(a, b) a=max(a,b)
#define chmin(a, b) a=min(a,b)
#define pb push_back
#define ff first
#define ss second
using namespace std;
using ll = long long;
using VI = vector <int>;
using PII = pair <int, int>;
int n, m, q;
const int N = 1e5+1;
const int M = 3*N;
const int N1 = 5001;
ll dp[N1][N1];
int nums[N];
struct Node {
    int l, r, mx;
    bool full;
} node[M];

Node merge(Node a, Node b) {
    Node res = {
        a.l + (a.full ? b.l : 0),
        (b.full ? a.r : 0) + b.r, 
        max(a.mx, b.mx),
        a.full&&b.full
    };
    res.mx = max({res.mx, res.l, res.r, a.r+b.l});
    return res;
}
void build(int l, int r, int head) {
    if (l == r) {
        int x = (nums[l] == 1);
        node[head] = {x, x, x, (bool)x};
        return;
    }
    int mid = (l+r)>>1;
    build(l, mid, head*2+1);
    build(mid+1, r, head*2+2);
    node[head] = merge(node[head*2+1], node[head*2+2]);
}
Node query(int l, int r, int L, int R, int head) {
    if (l > R || L > r) return {0, 0, 0, 1};
    if (L <= l && r <= R) return node[head];
    int mid = (l+r)>>1;
    return merge(
        query(l, mid, L, R, head*2+1),
        query(mid+1, r, L, R, head*2+2)
    );
}
vector<long long> minimum_costs(vector<int> h, vector<int> L, vector<int> R) {
    n = sz(h);
    q = sz(L);
    // cout << n << ' ' << q  << '\n';
    vector<long long> ans(q, 1e18);
    if (n < N1) {
        for (int i = 0; i < n; i++) {
            for (int j = i, cur = 0; j < n; j++) {
                cur = max(cur, h[j]);
                dp[i][j] = cur;
                if (j > i) dp[i][j] += dp[i][j-1];
            }
            for (int j = i, cur = 0; j >= 0; j--) {
                cur = max(cur, h[j]);
                dp[i][j] = cur;
                if (j < i) dp[i][j] += dp[i][j+1];
            }
        }
        for (int i = 0; i < q; i++) {
            int l = L[i], r = R[i];
            ll& res = ans[i];
            for (int mid = l; mid <= r; mid++) {
                chmin(res, dp[mid][l]+dp[mid][r]-h[mid]);
            }
        }
        return ans;
    } else {
        for (int i = 0; i < n; i++) nums[i] = h[i];
        build(0, n-1, 0);
        for (int i = 0; i < q; i++) {
            int cur = query(0, n-1, L[i], R[i], 0).mx;
            int len = R[i] - L[i] + 1;
            ans[i] = len * 2 - cur;
        }
    }
}

Compilation message (stderr)

meetings.cpp: In function 'std::vector<long long int> minimum_costs(std::vector<int>, std::vector<int>, std::vector<int>)':
meetings.cpp:90:1: warning: control reaches end of non-void function [-Wreturn-type]
   90 | }
      | ^

• Subtask 1: 4 / 4
• Subtask 2: 15 / 15
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 40