Submission #967237

#	Time	Username	Problem	Language	Result	Execution time	Memory
967237		vjudge1	Alternating Heights (CCO22_day1problem1)	C++17	25 / 25	577 ms	9604 KiB

Main

#include<bits/stdc++.h>

using namespace std;

int n,k,q, arr[3030], vis[3030], ans[3030], ck;
vector<int> vc[3030];

int check(int u){
    vis[u] = 1;
    for (int v : vc[u]) if(vis[v] == 1 || !vis[v] && check(v)) return 1;
    vis[u] = 2;
    return 0;
}

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n >> k >> q;
    for(int i = 1; i<=n; ++i) cin >> arr[i];
    for(int i = 1; i<=n; ++i){
        int l = i, r = n;
        ans[i] = i;
        while(l <= r){
            int mid = (l + r) >> 1, ck = 1;
            memset(vis, 0, sizeof(vis));
            for(int j = 1; j<=k; ++j) vc[j].clear();
            for(int j = i; j<mid; ++j){
                if(j&1) vc[arr[j+1]].push_back(arr[j]);
                else vc[arr[j]].push_back(arr[j+1]);
            }
            for(int j = i; j<=mid; ++j){
                if(!vis[arr[j]] && check(arr[j])){
                    ck = 0;
                    break;
                }
            }
            if(ck){
                ans[i] = mid;
                l = mid+1;
            }
            else r = mid - 1;
        }
    }
    while(q--){
        int l, r; cin >> l >> r;
        if(ans[l] >= r) {
            cout << "YES\n";
        } else {
            cout << "NO\n";
        }
    }
}

Compilation message (stderr)

Main.cpp: In function 'int check(int)':
Main.cpp:10:51: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   10 |     for (int v : vc[u]) if(vis[v] == 1 || !vis[v] && check(v)) return 1;
      |                                           ~~~~~~~~^~~~~~~~~~~

• Subtask 1: 4 / 4
• Subtask 2: 6 / 6
• Subtask 3: 7 / 7
• Subtask 4: 8 / 8