제출 #935168

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
935168		kim	Chorus (JOI23_chorus)	C++17	61 / 100	7024 ms	15448 KiB

chorus

#include<bits/stdc++.h>
using namespace std;
using ll=long long;
using pii=pair<int,int>;
#define f first
#define s second
#define eb emplace_back

const ll inf=1e18;

int a[1000005],b[1000005],pos[1000005],pos2[1000005];
ll dp2[2][1000005],qs[1000005];

ll f(int L,int R){
    int x=pos2[L];
    if(x>R) return 0;
    return qs[R]-qs[x-1]-L*(R-x+1);
}

void play2(int n,bool z){
    for(int i=1;i<=n;++i){
        dp2[z][i]=inf;
        for(int j=0;j<i;++j){
            if(pos2[j+1]>i){
                dp2[z][i]=min(dp2[z][i],dp2[!z][j]);
                break;
            }
            dp2[z][i]=min(dp2[z][i],-j*i+dp2[!z][j]-qs[pos2[j+1]-1]+1LL*pos2[j+1]*(j+1)-j+qs[i]-i-1);
        }
    }
}
struct line{
    ll m,c;
    line(ll m,ll c):m(m),c(c){}
    ll operator()(const ll x)const{return m*x+c;}
};
struct cht{
    deque<line> dq;
    bool check(line a,line b,line c){
        return (a.c-b.c)*(c.m-a.m)>=(a.c-c.c)*(b.m-a.m);
    }
    void insert(ll m,ll c){
        line f(m,c);
        while(dq.size()>1&&check(dq.end()[-2],dq.back(),f)) dq.pop_back();
        dq.eb(f);
    }
    ll qr(ll x){
        if(dq.empty()) return inf;
        while(dq.size()>1&&dq[1](x)<dq.front()(x)) dq.pop_front();
        return dq.front()(x);
    }
    void clear(){dq.clear();}
}dp;
void play(int n,bool z){
    dp.clear();
    int cur=0;
    for(int i=1;i<=n;++i){
        while(cur<i&&pos2[cur+1]<=i){
            dp.insert(-cur,dp2[!z][cur]-qs[pos2[cur+1]-1]+1LL*pos2[cur+1]*(cur+1)-cur);
            ++cur;
        }
        dp2[z][i]=dp.qr(i)+qs[i]-i-1;
        if(cur<i) dp2[z][i]=min(dp2[z][i],dp2[!z][cur]);
    }
}

int main(){
    ios::sync_with_stdio(false); cin.tie(0);

    int n,K; cin>>n>>K;
    string s; cin>>s;
    for(int i=0,ia=0,ib=0;i<s.length();++i){
        if(s[i]=='A') a[++ia]=i;
        else b[++ib]=i;
    }
    for(int i=1,j=1;i<=n;++i){
        while(j<=n&&b[j]<a[i]) ++j;
        pos[i]=j;
        qs[i]=qs[i-1]+j;
    }
    for(int i=1,j=1;i<=n;++i){
        while(j<=n&&pos[j]<=i) ++j;
        j=max(i,j);
        pos2[i]=j;
    }
    for(int i=1;i<=n;++i) dp2[1][i]=qs[i]-i;
    for(int k=2;k<=K;++k){
        // play(1,n,1,n,k&1);
        play(n,k&1);
    }
    cout<<dp2[K&1][n]<<endl;

    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

chorus.cpp: In function 'int main()':
chorus.cpp:72:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |     for(int i=0,ia=0,ib=0;i<s.length();++i){
      |                           ~^~~~~~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 24 / 24
• Subtask 3: 21 / 21
• Subtask 4: 0 / 26
• Subtask 5: 0 / 13