Submission #866987

#	Time	Username	Problem	Language	Result	Execution time	Memory
866987		HossamHero7	The short shank; Redemption (BOI21_prison)	C++14	45 / 100	2045 ms	13660 KiB

prison

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
const int N = 75005;
int P[N][20] , dp[N][2] , costt[N][20];
int t;
vector<int> v;
int cost(int l,int r){
    int ret = 0;
    int cur = l;
    for(int k=19;k>=0;k--){
        if(P[cur][k] <= r) {
            ret += costt[cur][k];
            cur = P[cur][k];
        }
    }
    ret += min(max(t-v[cur]+1,0),r-cur+1);
    return ret;
}
void calc(int l,int r,int opt1,int opt2,int k){
    if(l > r) return;
    int i = l + r >> 1;
    pair<int,int> opt{1e9,-1};
    for(int p=opt1;p<=min(opt2,i);p++){

        if(p) opt = min(opt,{dp[p-1][k-1&1]+cost(p,i),p});
        else opt = min(opt,{cost(0,i),p});
    }
    dp[i][k&1] = opt.first;
    calc(l,i-1,opt1,opt.second,k);
    calc(i+1,r,opt.second,opt2,k);
}
void solve(){
    int n,d;
    cin>>n>>d>>t;
    v.resize(n);
    for(auto &i:v) cin>>i;
    vector<int> starts;
    for(int i=n-1;i>=0;i--){
        while(starts.size()){
            int a = starts.back();
            if(v[a] >= v[i]+(a-i)) starts.pop_back();
            else break;
        }
        P[i][0] = (starts.size() ? starts.back() : n);
        costt[i][0] = min(max(t-v[i]+1,0),P[i][0] - i);
        starts.push_back(i);
    }
    for(int k=1;k<20;k++){
        for(int i=0;i<n;i++){
            if(P[i][k-1] == n) P[i][k] = n;
            else P[i][k] = P[P[i][k-1]][k-1];
            costt[i][k] = costt[i][k-1] + costt[P[i][k-1]][k-1];
        }
    }
    int lst = v[0];
    int prefix = (lst <= t);
    dp[0][0] = prefix;
    for(int j=1;j<n;j++) {
        if(v[j] > lst) lst ++;
        else lst = v[j];
        prefix += (lst <= t);
        dp[j][0] = prefix;
    }
    for(int k=1;k<=d;k++) calc(0,n-1,0,n-1,k);
    cout<<dp[n-1][d&1]<<endl;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);      cout.tie(0);
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }
    return 0;
}

Compilation message (stderr)

prison.cpp: In function 'void calc(int, int, int, int, int)':
prison.cpp:23:15: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   23 |     int i = l + r >> 1;
      |             ~~^~~
prison.cpp:27:39: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   27 |         if(p) opt = min(opt,{dp[p-1][k-1&1]+cost(p,i),p});
      |                                      ~^~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 10 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20