Submission #667036

#	Time	Username	Problem	Language	Result	Execution time	Memory
667036		Darren0724	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	10 ms	5976 KiB

ho_t2

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(),x.end()
int INF=1e18;
signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n,k;cin>>n>>k;
    string s;cin>>s;
    vector<int> pre(n);
    pre[0]=(s[0]=='O');
    for(int i=1;i<n;i++){
        pre[i]=pre[i-1]+(s[i]=='O');
    }
    auto f=[&](int a,int b)->int{
        if(a>b){
            return 0;
        }
        if(a==0){
            return pre[b];
        }
        return pre[b]-pre[a-1];
    };
    vector<int> dp1(n),dp2(n);
    int cnt=0;
    queue<int> q;
    for(int i=0;i<n;i++){
        if(s[i]=='J'){
            q.push(i);
        }
        if(q.size()>k){
            q.pop();
        }
        if(q.size()<k){
            dp1[i]=-INF;
        }
        else{
            dp1[i]=q.front();
        }
    }
    while(q.size()){
        q.pop();
    }
    for(int i=n-1;i>=0;i--){
        if(s[i]=='I'){
            q.push(i);
        }
        if(q.size()>k){
            q.pop();
        }
        if(q.size()<k){
            dp2[i]=INF;
        }
        else{
            dp2[i]=q.front();
        }
    }
    int j=n-1;
    int ans=INF;
    for(int i=n-2;i>=0;i--){
        while(f(i+1,j-2)>=k){
            j--;
        }
        if(f(i+1,j-1)>=k){
            ans=min(ans,dp2[j]-dp1[i]+1-k*3);
        }
    }
    if(ans>=n){
        cout<<-1<<endl;
    }
    else{
        cout<<ans<<endl;
    }

    return 0;
}

Compilation message (stderr)

ho_t2.cpp: In function 'int main()':
ho_t2.cpp:32:20: warning: comparison of integer expressions of different signedness: 'std::queue<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   32 |         if(q.size()>k){
      |            ~~~~~~~~^~
ho_t2.cpp:35:20: warning: comparison of integer expressions of different signedness: 'std::queue<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   35 |         if(q.size()<k){
      |            ~~~~~~~~^~
ho_t2.cpp:49:20: warning: comparison of integer expressions of different signedness: 'std::queue<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   49 |         if(q.size()>k){
      |            ~~~~~~~~^~
ho_t2.cpp:52:20: warning: comparison of integer expressions of different signedness: 'std::queue<long long int>::size_type' {aka 'long unsigned int'} and 'long long int' [-Wsign-compare]
   52 |         if(q.size()<k){
      |            ~~~~~~~~^~
ho_t2.cpp:26:9: warning: unused variable 'cnt' [-Wunused-variable]
   26 |     int cnt=0;
      |         ^~~

• Subtask 1: 1 / 1
• Subtask 2: 12 / 12
• Subtask 3: 87 / 87