//chockolateman
#include<bits/stdc++.h>
using namespace std;
const int INF = 1e9+2;
int N,D,a[300005],dp[300005],max_reach[300005],p[300005],s[300005],val[300005],prv_small[300005],nxt_small[300005],st[1200005];
pair<int,int> temp[300005];
int find_Sett(int i)
{
if(p[i]==i)
return i;
p[i] = find_Sett(p[i]);
return p[i];
}
bool is_Same_Sett(int i,int j)
{
return find_Sett(i)==find_Sett(j);
}
int get_val(int i)
{
return val[find_Sett(i)];
}
void union_Sett(int i,int j)
{
if(is_Same_Sett(i,j))
return ;
int x = find_Sett(i);
int y = find_Sett(j);
if(s[x] >= s[y])
{
p[y] = x;
s[x] += s[y];
val[x] = min(val[x],val[y]);
}
else
{
p[x] = y;
s[y] += s[x];
val[y] = min(val[y],val[x]);
}
}
void update(int pos,int val,int v = 1,int start = 1,int end = N)
{
if(start==end)
{
st[v] = val;
return;
}
int mid = (start + end)/2;
if(pos <= mid)
update(pos,val,2*v,start,mid);
else
update(pos,val,2*v+1,mid+1,end);
st[v] = max(st[2*v],st[2*v+1]);
}
int query(int l,int r,int v = 1,int start = 1,int end = N)
{
if(start==l && end==r)
return st[v];
int mid = (start + end)/2;
if(r <= mid)
return query(l,r,2*v,start,mid);
else if(l > mid)
return query(l,r,2*v+1,mid+1,end);
else
return max(query(l,mid,2*v,start,mid),query(mid+1,r,2*v+1,mid+1,end));
}
int main()
{
scanf("%d%d",&N,&D);
for(int i = 1 ; i <= N ; i++)
{
scanf("%d",&a[i]);
a[i]++;
p[i] = i;
s[i] = 1;
val[i] = i;
temp[i] = {a[i],i};
}
stack<pair<int,int>> ord;
ord.push({0,0});
for(int i = 1 ; i <= N ; i++)
{
while(ord.top().first > a[i])
ord.pop();
prv_small[i] = ord.top().second;
if(prv_small[i]==0 || i - prv_small[i] > D)
prv_small[i] = i;
ord.push({a[i],i});
}
while(!ord.empty())
ord.pop();
ord.push({0,N+1});
for(int i = N ; i >= 1 ; i--)
{
while(ord.top().first >= a[i])
ord.pop();
nxt_small[i] = ord.top().second;
if(nxt_small[i]==N+1 || nxt_small[i] - i > D)
nxt_small[i] = i;
ord.push({a[i],i});
}
sort(temp+1,temp+N+1);
for(int j = 1 ; j <= N ; j++)
{
int i = temp[j].second;
union_Sett(i,prv_small[i]);
union_Sett(i,nxt_small[i]);
max_reach[i] = get_val(i);
}
for(int i = 1 ; i <= N ; i++)
temp[i] = {a[i],-i};
sort(temp+1,temp+N+1);
int ans = 0;
for(int j = 1 ; j <= N ; j++)
{
int i = -temp[j].second;
dp[i] = query(max_reach[i],i) + 1;
update(i,dp[i]);
ans = max(ans,dp[i]);
}
printf("%d\n",ans);
return 0;
}
Compilation message (stderr)
Main.cpp: In function 'int main()':
Main.cpp:80:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
80 | scanf("%d%d",&N,&D);
| ~~~~~^~~~~~~~~~~~~~
Main.cpp:83:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
83 | scanf("%d",&a[i]);
| ~~~~~^~~~~~~~~~~~
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