Submission #734065

#	Time	Username	Problem	Language	Result	Execution time	Memory
734065		myrcella	The short shank; Redemption (BOI21_prison)	C++17	100 / 100	981 ms	436728 KiB

prison

//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];
vector <int> edge[maxn];
int hson[maxn];
pq <pii> s;
int vis[maxn];

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

int dfs(int u) {
	int val = 0; vis[u] = 1;
	for (int v:edge[u]) {
		int tmp = dfs(v);
		if (tmp>val) val=tmp,hson[u] = v;
	}
	s.push({val+1,u});
	return val+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]);
		}
	vector <pii> tmp;
	int ans = n;
	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 (le[i]==0) ans--;
			else {
				while (!tmp.empty() and tmp.back().fi>=le[i]) edge[i].pb(tmp.back().se),tmp.pop_back();
				tmp.pb({le[i],i});
			}
		}
	}
	memset(hson,-1,sizeof(hson));
	for (int i = n-1;i>=0;i--)
		if (le[i]!=maxn and le[i]!=0 and vis[i]==0) dfs(i);
	memset(vis,0,sizeof(vis));
	rep(i,0,d) {
		while (!s.empty() and vis[s.top().se]) s.pop();
		if (s.empty()) break;
		ans -= s.top().fi;
		int u = s.top().se;
		while (u!=-1) vis[u]=1,u=hson[u];
	}
	cout<<ans;
	return 0;
}

Compilation message (stderr)

prison.cpp: In function 'int main()':
prison.cpp:69:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |     int mid = l+r>>1;
      |               ~^~

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