Submission #334592

#	Time	Username	Problem	Language	Result	Execution time	Memory
334592		rocks03	Finding Routers (IOI20_routers)	C++14	100 / 100	8 ms	768 KiB

routers

#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

int use_detector(int x);
vector<int> ask;
int use_use_detector(int x){
    if(ask[x] != -1)
        return ask[x];
    return (ask[x] = use_detector(x));
}
 
vector<int> find_routers(int l, int n, int q){
    ask.resize(l + 1, -1);
    vector<int> ans(n);
    vector<int> mn(n, 0), mx(n, l);
    ans[0] = 0;
    for(int i = 1; i < n; i++){
        int l = max(mn[i-1], ans[i - 1]), r = mx[i];
        while(r - l > 1){
            int m = (l + r) / 2;
            int idx = use_use_detector(m);
            for(int j = idx; j < n; j++){
                mn[j] = max(mn[j], m);
            }
            for(int j = idx; j >= 0; j--){
                mx[j] = min(mx[j], m);
            }
            if(i <= idx){
                r = m;
            } else{
                l = m;
            }
        }
        ans[i] = 2 * (r - 1 - ans[i - 1]) + ans[i - 1];
    }
    return ans;
}

Compilation message (stderr)

routers.cpp:2: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    2 | #pragma GCC optimization("O3")
      | 
routers.cpp:3: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    3 | #pragma GCC optimization("unroll-loops")
      |

• Subtask 1: 16 / 16
• Subtask 2: 21 / 21
• Subtask 3: 23 / 23
• Subtask 4: 40 / 40