Submission #448549

#	Time	Username	Problem	Language	Result	Execution time	Memory
448549		Edbert2397	Martian DNA (BOI18_dna)	C++14	100 / 100	72 ms	4476 KiB

dna

/*
~2021~
*/
# include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
typedef long long ll;
#define pii pair<int,int>
#define debug(x) cout << #x << '=' << x << endl;
const int N = 2e5 + 5;
const int INF = 1e9;
const ll mod = 1e9+7;
int need[N],arr[N],n,k,q,byk[N];
bool valid(int x){
    for(int i = 0;i<k;i++) byk[i] = 0;
    int cnt = 0;
    for(int i = 1;i<=n;i++){
        if(i > x){
            if(byk[arr[i-x]] == need[arr[i-x]]) cnt--;
            byk[arr[i-x]]--;
        }
        byk[arr[i]]++;
        if(byk[arr[i]] == need[arr[i]]) cnt++;
        if(cnt == q) return true;
    }
    return false;
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    //freopen(,r,stdin);
    //freopen(,w,stdout);
    cin>>n>>k>>q;
    for(int i = 1;i<=n;i++) cin>>arr[i];
    for(int i = 1;i<=q;i++){
        int x,y;
        cin>>x>>y;
        need[x] = y;
    }
    int ki = 1,ka = n;
    int pos = -1;
    while(ki <= ka){
        int mid = (ki + ka)/2;
        if(valid(mid)){
            pos = mid;
            ka = mid-1;
        }
        else{
            ki = mid + 1;
        }
    }
    if(pos == -1) cout<<"impossible"<<endl;
    else cout<<pos<<endl;
}

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