Submission #423369

#	Time	Username	Problem	Language	Result	Execution time	Memory
423369		juggernaut	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	34 ms	3104 KiB

ho_t2

#include<bits/stdc++.h>
#define fr first
#define sc second
using namespace std;
void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
typedef long long ll;
#define USING_ORDERED_SET 0
#if USING_ORDERED_SET
#include<bits/extc++.h>
using namespace __gnu_pbds;
template<class T>using ordered_set=tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
#endif
template<class T>void umax(T &a,T b){if(a<b)a=b;}
template<class T>void umin(T &a,T b){if(b<a)a=b;}
#ifdef IOI2021SG
    #define printl(args...)printf(args)
#else
    #define printl(args...)((void)0)
#endif
int n,k;
string s;
int pref[200005][3];
int main(){
    //ios_base::sync_with_stdio(0);
    //cin.tie(0);
    cin>>n>>k>>s;
    s=" "+s;
    for(int i=1;i<=n;i++){
        pref[i][0]=pref[i-1][0]+(s[i]=='J');
        pref[i][1]=pref[i-1][1]+(s[i]=='O');
        pref[i][2]=pref[i-1][2]+(s[i]=='I');
    }
    int mn=1e9;
    for(int i=1;i<=n;i++){
        int pivot=i-1;
        int l=i;
        int r=n;
        while(l<r){
            int mid=(l+r)>>1;
            if(pref[mid][0]-pref[pivot][0]>=k)r=mid;
            else l=mid+1;
        }
        if(pref[l][0]-pref[pivot][0]<k)continue;
        r=n;
        pivot=l-1;
        while(l<r){
            int mid=(l+r)>>1;
            if(pref[mid][1]-pref[pivot][1]>=k)r=mid;
            else l=mid+1;
        }
        if(pref[l][1]-pref[pivot][1]<k)continue;
        r=n;
        pivot=l-1;
        while(l<r){
            int mid=(l+r)>>1;
            if(pref[mid][2]-pref[pivot][2]>=k)r=mid;
            else l=mid+1;
        }
        if(pref[l][2]-pref[pivot][2]<k)continue;
        umin(mn,l-i+1);
    }
    if(mn==int(1e9))puts("-1");
    else printf("%d",mn-3*k);
}

Compilation message (stderr)

ho_t2.cpp: In function 'void usaco(std::string)':
ho_t2.cpp:5:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ho_t2.cpp:5:66: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    5 | void usaco(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
      |                                                           ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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