Submission #935052

#	Time	Username	Problem	Language	Result	Execution time	Memory
935052		kim	Chorus (JOI23_chorus)	C++17	61 / 100	1133 ms	336408 KiB

chorus

#include<bits/stdc++.h>
using namespace std;
using ll=long long;
#define f first
#define s second

const ll inf=1e18;

int a[5005],b[5005],pos[5005];
ll dp[5005][5005],cost[5005][5005];

void play(int l,int r,int optl,int optr,int z){
    if(l>r) return;
    int mid=l+r>>1;
    pair<ll,int> best(inf,0);
    for(int i=optl;i<=min(mid,optr);++i){
        best=min(best,{dp[z-1][i-1]+cost[i][mid],i});
    }
    dp[z][mid]=best.f;
    play(l,mid-1,optl,best.s,z);
    play(mid+1,r,best.s,optr,z);
}

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;
    }
    for(int i=1;i<=n;++i){
        for(int j=i;j<=n;++j){
            cost[i][j]=cost[i][j-1]+max(0,pos[j]-i);
        }
    }
    for(int i=1;i<=n;++i) dp[1][i]=cost[1][i];
    for(int k=2;k<=K;++k){
        play(1,n,1,n,k);
    }
    cout<<dp[K][n];

    return 0;
}

Compilation message (stderr)

chorus.cpp: In function 'void play(int, int, int, int, int)':
chorus.cpp:14:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   14 |     int mid=l+r>>1;
      |             ~^~
chorus.cpp: In function 'int main()':
chorus.cpp:29:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     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