Submission #1163832

#	Time	Username	Problem	Language	Result	Execution time	Memory
1163832		8pete8	Chorus (JOI23_chorus)	C++17	61 / 100	7090 ms	5304 KiB

chorus

#include<iostream>
#include<stack>
#include<map>
#include<vector>
#include<string>
#include<cassert>
#include<unordered_map>
#include <queue>
#include <cstdint>
#include<cstring>
#include<limits.h>
#include<cmath>
#include<set>
#include<algorithm>
#include <iomanip>
#include<numeric>
#include<bitset>
using namespace std;
#define ll long long
#define f first
#define s second
#define pii pair<int,int>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-lopps")
#define int long long
#define double long double
using namespace std;
const int mod=1e9+7,mxn=1e6+5,inf=1e18,minf=-1e18,lg=30;
//#undef int
int n,k,m,x,q;
void setIO(string name){
	ios_base::sync_with_stdio(0); cin.tie(0);		
	freopen((name+".in").c_str(),"r",stdin);
	freopen((name+".out").c_str(),"w",stdout);
}
vector<int>A,B;
int prefB[mxn+10];
int pref[mxn+10],cntA[mxn+10];
int getcost(int l,int r){
    l--,r--;
    return (pref[A[r]]-pref[max(A[l],B[l])-1])-(cntA[A[r]]-cntA[max(A[l],B[l])-1])*(prefB[B[l]-1]);
}
pii dp[mxn+10];
int check(int lambda){
    dp[0]={0,0};
    for(int i=1;i<=n;i++)dp[i]={inf,inf};
    for(int i=1;i<=n;i++){
        for(int j=0;j<i;j++)dp[i]=min(dp[i],{dp[j].f+getcost(j+1,i)+lambda,dp[j].s+1});
    }
    return dp[n].s;
}
int32_t main(){
    fastio
    cin>>n>>k;
    string a;cin>>a;
    int c=0;
    for(int i=1;i<=2*n;i++){
        if(a[i-1]=='A')A.pb(i),cntA[i]++;
        else B.pb(i),c++;
        prefB[i]=c;
        if(a[i-1]=='A')pref[i]=prefB[i];
        pref[i]+=pref[i-1],cntA[i]+=cntA[i-1];
    }
    int l=0,r=inf,ans=inf;
    while(l<=r){
        int mid=l+(r-l)/2;
        //check -> left most point (min)
        if(check(mid)<=k)r=mid-1,ans=min(ans,mid);
        else l=mid+1;
    }
    check(ans);
    cout<<dp[n].f-(ans*k);
    /*
    L=j, 
    dp[i][k] = dp[j][k-1] + (pref[AR]-pref[BL]) - (cntA[AR]-cntA[BL])*(prefB[BL-1]);
    dp[j][k-1] + sum of (cnt of Bj Ai where j<i) in range (first B , last A) 
    - (cnt of A in range [firsB,last A])*(cnt of Bj<BL)
    */
}

Compilation message (stderr)

chorus.cpp:32:40: warning: bad option '-funroll-lopps' to pragma 'optimize' [-Wpragmas]
   32 | #pragma GCC optimize ("03,unroll-lopps")
      |                                        ^
chorus.cpp:39:23: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   39 | void setIO(string name){
      |                       ^
chorus.cpp:47:24: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   47 | int getcost(int l,int r){
      |                        ^
chorus.cpp:52:21: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   52 | int check(int lambda){
      |                     ^
chorus.cpp:60:14: warning: bad option '-funroll-lopps' to attribute 'optimize' [-Wattributes]
   60 | int32_t main(){
      |              ^
chorus.cpp: In function 'void setIO(std::string)':
chorus.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |         freopen((name+".in").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
chorus.cpp:42:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |         freopen((name+".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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