| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 833089 | CSQ31 | Chorus (JOI23_chorus) | C++17 | 0 ms | 0 KiB |
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;
#define pb push_back
#define fi first
#define se second
#define sz(a) (int)(a.size())
#define all(a) a.begin(),a.end()
#define lb lower_bound
#define ub upper_bound
#define owo ios_base::sync_with_stdio(0);cin.tie(0);
#define debug(...) fprintf(stderr, __VA_ARGS__),fflush(stderr)
#define time__(d) for(long blockTime = 0; (blockTime == 0 ? (blockTime=clock()) != 0 : false);\
debug("%s time : %.4fs\n", d, (double)(clock() - blockTime) / CLOCKS_PER_SEC))
typedef long long int ll;
typedef long double ld;
typedef pair<ll,ll> PII;
typedef pair<int,int> pii;
typedef vector<vector<int>> vii;
typedef vector<vector<ll>> VII;
ll gcd(ll a,ll b){if(!b)return a;else return gcd(b,a%b);}
const int MAXN = 1e6+5;
int a[MAXN],n,k;
ll dp[2222][2222],p[MAXN];
struct line{
ll m = 0,c = 0;
int cnt = 0;
line(){}
line(ll _m,ll _c,int _cnt):m(_m),c(_c),cnt(_cnt){}
ll eval(ll x){return m*x+c;}
};
deque<line>hull;
void add(line t){
while(sz(hull)>1){
line a = hull[sz(hull)-2];
line b = hull[sz(hull)-1];
//inter(t,a) >= inter(t,b)
if((t.c - a.c) * (b.m - t.m) >= (a.m - t.m) * (t.c - b.c))hull.pop_back();
else break;
}
hull.push_back(t);
}
int num = 0;
ll query(ll x){
while(sz(hull)>1 && hull[1].eval(x) >= hull[0].eval(x))hull.pop_front();
num = hull[0].cnt;
return hull[0].eval(x);
}
int main()
{
string s;
cin>>n>>k>>s;
int cur = 0,nxt = 0;
for(int i=0;i<2*n;i++){
if(s[i] == 'A')cur++;
else a[++nxt] = cur;
}
for(int i=1;i<=n;i++)p[i] = p[i-1]+a[i];
for(int i=0;i<=n;i++){
for(int j=0;j<=k;j++){
dp[i][j] = 1e18;
}
dp[0][0] = 0;
for(int x=1;x<=k;x++){
int l = -1;
hull.clear();
for(int i=1;i<=n;i++){
while(l+1<=i && a[l+1] <= i){
l++;
hull.pb(line(l,-p[l]-dp[l][x-1],0));
}
dp[i][x] = l*i - p[l] - query(i);
/*
for(int j=l;j>=0;j--){
dp[i][x] = min(dp[i][x],dp[j][x-1] + (l-j)*i - (p[l]-p[j]));
}
* (l*i -p[l]) - j*i + dp[j][x-1] + p[j];
*/
}
}
cout<<dp[n][k];
}