Submission #927088

#	Time	Username	Problem	Language	Result	Execution time	Memory
927088		vjudge1	Martian DNA (BOI18_dna)	C++17	0 / 100	450 ms	18512 KiB

dna

// #pragma GCC target ("avx2")
// #pragma GCC optimization ("O3")
// #pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>

#define int long long
#define ff first
#define ss second
#define pb push_back
#define yes cout<<"Yes\n"
#define no cout<<"No\n"
#define no1 cout<<"-1\n"

using namespace std;

const int N = 2e5+100;
const int M = 1e5+10;
const int INF = 1e18;
const int mod = 1e9+7;
  
// int binpow (int a, int n) {
// 	if (n == 0)
// 		return 1;
// 	if (n % 2 == 1)
// 		return (binpow (a, n-1) * a)%mod;
// 	else {
// 		int b = binpow (a, n/2);
// 		return (b * b)%mod;
// 	}
// }

int n,k,R;
int a[N];
map<int,int> mn;
map<int,int> mx;
map<int,int> m;
int d[N];

void solve(){
    cin>>n>>k>>R;
    for(int i = 1;i<=n;i++){
        cin>>a[i];
        if(!mn[a[i]]) mn[a[i]] = i;
        mx[a[i]] = i;
        m[a[i]]++;
    }
    int l = INF;
    int r = 0;
    while(R--){
        int b,q;
        cin>>b>>q;
        d[b] = q;
        if(m[b] < q){
            cout<<"impossible\n";
            return;
        }
        l = min(l,mn[b]);
        r = max(r,mx[b]);
    }
    m.clear();
    for(int i = l;i<=r;i++){
        m[a[i]]++;
    }
    int bl = l;
    int br = r;
    while(1){
        if(l==r){
            break;
        }
        int x = m[a[l]]-1-d[a[l]];
        int y = m[a[r]]-1-d[a[r]];
        if(x<0 && y<0) break;
        else if(y<0 || x>y){
            m[a[l]]--;
            l++;
        }
        else{
            m[a[r]]--;
            r--;
        }
    }
    m.clear();
    for(int i = bl;i<=br;i++){
        m[a[i]]++;
    }
    while(1){
        if(bl==br){
            break;
        }
        int x = m[a[bl]]-1-d[a[bl]];
        int y = m[a[br]]-1-d[a[br]];
        if(x<0 && y<0) break;
        else if(x<0 || x<y){
            m[a[br]]--;
            br--;
        }
        else{
            m[a[bl]]--;
            bl++;
        }
    }
    cout<<min(r-l+1,br-bl+1)<<'\n';
}

signed main(){
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr);
    // cout.tie(nullptr);
    int t = 1; 
    // cin>>t;
    //   cout<<"";
    for(int i = 1;i<=t;i++){
        // cout<<"Case "<<i<<": ";
        solve();
        // cout<<'\n';
    }
}

• Subtask 1: 0 / 16
• Subtask 2: 0 / 24
• Subtask 3: 0 / 28
• Subtask 4: 0 / 32