Submission #733843

#TimeUsernameProblemLanguageResultExecution timeMemory
733843oolimryThe short shank; Redemption (BOI21_prison)C++17
10 / 100
880 ms266128 KiB
//by szh
#include<bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}

const int maxn = 2e6+10;
int n,d,T;
int t[maxn];
int le[maxn];
int mn[maxn][21];
int lg[maxn];

int query(int l,int r) {
  int tmp = lg[r-l+1];
  return min(mn[l][tmp],mn[r-(1<<tmp)+1][tmp]);
}

pair<ll,int> tree[maxn*4],add[maxn*4];

void update(int c,int cl,int cr,int l,int r,ll val1,int val2) {
  if (l<=cl and cr<=r) {
    tree[c].fi += val1;
    tree[c].se += val2;
    add[c].fi += val1;
    add[c].se += val2;
    return;
  }
  int mid=cl+cr>>1;
  if (add[c]!=MP(0ll,0)) {
    tree[c<<1].fi += add[c].fi;
    tree[c<<1|1].fi += add[c].fi;
    tree[c<<1].se += add[c].se;
    tree[c<<1|1].se += add[c].se;
    add[c<<1].fi += add[c].fi, add[c<<1|1].fi += add[c].fi;
    add[c<<1].se += add[c].se, add[c<<1|1].se += add[c].se;
    add[c] = {0ll,0};
  }
  if (l<=mid) update(c<<1,cl,mid,l,r,val1,val2);
  if (r>mid) update(c<<1|1,mid+1,cr,l,r,val1,val2);
  tree[c] = tree[c<<1];
  if (tree[c<<1|1].fi>tree[c].fi or (tree[c<<1|1].fi==tree[c].fi and tree[c<<1|1].se<tree[c].se)) tree[c] = tree[c<<1|1];
  return;
}

pair<ll,int> solve(int cost) {
  //the cost of installing each wall is cost
  rep(i,1,maxn*4) tree[i] = {- 1e18,0},add[i] = {0,0};
  ll tmp = 1e18;
  if (le[0]==0) tmp++;
  update(1,0,n-1,0,0,tmp,0);
  //debug((le[0]!=maxn));
  //debug(tree[1].fi);
  rep(i,1,n) {
    //install a wall here
    pair<ll,int> tmp = {tree[1].fi - cost,tree[1].se+1};
    update(1,0,n-1,i,i,1e18 + tmp.fi,tmp.se);
    if (le[i]<=i) update(1,0,n-1,le[i],i,1,0);
  }
  //cout<<cost<<" "<<tree[1].fi<<" "<<tree[1].se<<endl;
  return tree[1];

}

int main() {
  //	freopen("input.txt","r",stdin);	
  std::ios::sync_with_stdio(false);cin.tie(0);
  cin>>n>>d>>T;
  rep(i,0,n) cin>>t[i],mn[i][0] = t[i]-i;
  lg[1] = 0;
  rep(i,2,maxn) lg[i] = lg[i/2]+1;
  for (int i = n-1;i>=0;i--) 
    rep(j,1,21) {
    if (i+(1<<j)>n) break;
    mn[i][j] = min(mn[i][j-1],mn[i+(1<<(j-1))][j-1]);
  }
  rep(i,0,n) {
    if (t[i]<=T) le[i] = maxn;
    else {
      int l = 0,r=i;
      while (l<r) {
        int mid = l+r>>1;
        if (mid==i or query(mid,i-1)+i>T) r=mid;
        else l = mid+1;
      }
      le[i] = l;
    }
  }
  if (d==1) {
    pq <int> q;
    int cnt = 0;
    rep(i,0,n) if (le[i]==0) cnt++;
    int mx = 0;
    for (int i=n-1;i>=0;i--) {
      if (le[i]!=0) q.push({le[i]});
      while (!q.empty() and q.top()>i) q.pop();
      mx = max(mx,SZ(q));
    }
    cout<<n-cnt-mx<<"\n";
    return 0;
  }
  //monge
  int l = 0, r = n;
  pair<ll,int> ans;
  while (l<r) {
    int mid=l+r>>1;
    ans = solve(mid);
    if (ans.se<=d) r = mid;
    else l = mid+1;//penalty too small
  }
  ans = solve(r);
  cout<<n-(ans.fi+ans.se*d);
  return 0;
}

Compilation message (stderr)

prison.cpp: In function 'void update(int, int, int, int, int, long long int, int)':
prison.cpp:46:13: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   46 |   int mid=cl+cr>>1;
      |           ~~^~~
prison.cpp: In function 'int main()':
prison.cpp:99:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   99 |         int mid = l+r>>1;
      |                   ~^~
prison.cpp:123:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  123 |     int mid=l+r>>1;
      |             ~^~
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