This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
//#include<bits/extc++.h>
//__gnu_pbds
#define int ll
const int N = 1e6+5;
pair<ll,int> dp[N];
int Bpa[N];
ll Bpasum[N];
int n,K;
ll cost(int i,int j){
int l = i;
int r = j+1;
while(r-l>1){
int mid = (l+r)/2;
if(Bpa[mid]<j) l = mid;
else r = mid;
}
int cnt = l-i;
ll ans = Bpasum[l]-Bpasum[i];
return cnt*j-ans;
}
struct seg{
int pos;int l;int r;
seg(int _pos,int _l,int _r):pos(_pos),l(_l),r(_r){}
};
bool ok(int v){
for(int i=0;i<=n;i++) dp[i] = {1e18,0};
dp[0]={0,0};
dp[n+1] = {1e15,0};
deque<seg> dq;
dq.push_back(seg(0,1,n));
for(int i=1;i<=n;i++){
while(dq.size()){
if(dq[0].r<i) dq.pop_front();
else break;
}
dp[i] = {dp[dq[0].pos].first+cost(dq[0].pos,i)+v,dp[dq[0].pos].second+1};
while(dq.size()){
if(dp[dq.back().pos].first+cost(dq.back().pos,dq.back().l)>dp[i].first+cost(i,dq.back().l)) dq.pop_back();
else break;
}
if(dq.empty()) dq.push_back(seg(i,i+1,n));
else{
seg pseg = dq.back();
dq.pop_back();
int l = pseg.l;int r = pseg.r+1;
while(r-l>1){
int mid = (l+r)/2;
if(dp[pseg.pos].first+cost(pseg.pos,mid)>dp[i].first+cost(i,mid)) r=mid;
else l = mid;
}
dq.push_back(seg(pseg.pos,pseg.l,l));
if(l!=n) dq.push_back(seg(i,l+1,n));
}
}
//cout<<(dp[n].second<=K)<<" "<<dp[n].first<<" "<<v<<"\n";
return (dp[n].second<=K);
}
signed main(){
ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
cin>>n>>K;
int pa = 0;
int pb = 0;
for(int i=1;i<=2*n;i++){
char a = getchar();
if(a=='A') pa++;
if(a=='B') Bpa[++pb]=pa;
}
for(int i=1;i<=n;i++){
Bpasum[i] = Bpasum[i-1]+Bpa[i];
}
ll l = -1;ll r = 1e9;
while(r-l>1){
ll mid = l+((r-l)/2);
if(ok(mid)) r = mid;
else l = mid;
}
ok(r);
//cout<<r<<"\n";
cout<<dp[n].first-r*K<<"\n";
return 0;
}
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |