Submission #114008

#	Time	Username	Problem	Language	Result	Execution time	Memory
114008		shayan_p	Construction of Highway (JOI18_construction)	C++14	100 / 100	1989 ms	31332 KiB

construction

// High above the clouds there is a rainbow...

#include<bits/stdc++.h>

#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

const int maxn=1e5+10,SQ=350;

int a[maxn],fn[maxn],par[maxn],state[maxn],arr[maxn],A[maxn],B[maxn],C;
vector<int>v[maxn];

pii p[SQ+10];

void add(int pos,int x){
    for(pos=pos+3;pos<maxn;pos+=(pos & -pos))
	fn[pos]+=x;
}
int ask(int pos){
    int ans=0;
    for(pos=pos+3;pos>0;pos-=(pos & -pos))
	ans+=fn[pos];
    return ans;
}

int sp[20][2*maxn],h[maxn],start[maxn];
vector<int>vec;

void dfs(int u){
    if(par[u]!=-1) h[u]=h[par[u]]+1;  
    start[u]=sz(vec), vec.PB(u);
    for(int i=1;i<20;i++){
	sp[i][u]=sp[i-1][u];
	if(sp[i][u]!=-1) sp[i][u]=sp[i-1][sp[i-1][u]];
    }
    for(int y:v[u]){
	dfs(y);
    }
    if(par[u]!=-1) vec.PB(par[u]);
}
void prep(){
    for(int i=0;i<sz(vec);i++){
	sp[0][i]=h[vec[i]];
    }
    for(int i=1;i<20;i++){
	for(int j=0;j<sz(vec);j++){
	    sp[i][j]=sp[i-1][j];
	    if(j+(1<<(i-1))<sz(vec)) sp[i][j]=min(sp[i][j],sp[i-1][j+(1<<(i-1))]);
	}
    }
}
int lca(int a,int b){
    a=start[a], b=start[b];
    if(a>b) swap(a,b);
    int id=31-__builtin_clz(b-a+1);
    return min(sp[id][a],sp[id][b+1-(1<<id)]);
}

int main(){
    ios_base::sync_with_stdio(false);cin.tie(0);
    int n;cin>>n;
    for(int i=0;i<n;i++){
	cin>>a[i];
	arr[i]=a[i];
    }
    sort(arr,arr+n);
    C=unique(arr,arr+n)-arr;
    for(int i=0;i<n;i++){
	a[i]=lower_bound(arr,arr+C,a[i])-arr;
    }

    par[0]=-1;
    for(int i=0;i<n-1;i++){
	cin>>A[i]>>B[i];
	par[--B[i]]=--A[i];
	v[A[i]].PB(B[i]);
    }
    
    dfs(0);
    prep();
    
    for(int l=0;l<n-1;l+=SQ){
	int r=min(n-1,l+SQ);
	++C;
	for(int i=l;i<r;i++){
	    ll ans=0;
	    int x=A[i],lst=x;
	    state[B[i]]=C;
	    while(x>=0 && state[x]!=C){
		state[x]=C;
		ans+=ask(a[x]-1);
		add(a[x],1);
		lst=x=par[x];
	    }
	    int bh=-1,SZ=0;
	    for(int j=i-1;j>=l;j--){
		int hh=lca(A[i],B[j]);
		if(bh<hh) p[SZ++]={hh-bh,a[B[j]]}, bh=hh;
	    }
	    for(int j=SZ-1;j>=0;j--){
		ans+= 1ll*p[j].F * ask(p[j].S-1);
		add(p[j].S,p[j].F);
	    }
	    x=A[i];
	    while(x!=lst){
		add(a[x],-1);
		x=par[x];
	    }
	    for(int j=0;j<SZ;j++){
		add(p[j].S,-p[j].F);
	    }
	    cout<<ans<<"\n";
	}
	++C;
	for(int i=r-1;i>=l;i--){
	    int x=B[i];
	    while(x>=0 && state[x]!=C){
		state[x]=C;
		a[x]=a[B[i]];
		x=par[x];
	    }
	}
    }
    return 0;
}
// Deathly mistakes:
//  * Read the problem curfully.
//  * Check maxn.
//  * Overflows.

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 84 / 84