Submission #540712

#	Time	Username	Problem	Language	Result	Execution time	Memory
540712		jamezzz	Dynamic Diameter (CEOI19_diameter)	C++17	100 / 100	4045 ms	229308 KiB

diameter

#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 2023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef pair<ll,int> li;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));

#define mod 1000000007

inline int add(int a,int b){
	int r=a+b;
	while(r>=mod)r-=mod;
	while(r<0)r+=mod;
	return r;
}

inline int mult(int a,int b){
	return (int)(((ll)(a*b))%mod);
}

inline int rd(){
	int x=0;
	char ch=getchar_unlocked();
	while(!(ch&16))ch=getchar();//keep reading while current character is whitespace
    while(ch&16){//this will break when ‘\n’ or ‘ ‘ is encountered
		x=(x<<3)+(x<<1)+(ch&15);
		ch=getchar_unlocked();
	}
	return x;
}

#define maxn 100005

struct edge{
	int u,v;ll w;
	vector<int> comp;
	vector<ii> range;
};

struct node{
	int s,e;ll ans;
	vector<li> v;
	vector<ll> lz;
	vector<ii> ranges;
	
	void init(int i,int l,int r){
		v[i]={0,l};
		lz[i]=0;
		if(l==r)return;
		int m=(l+r)>>1;
		init(2*i+1,l,m);
		init(2*i+2,m+1,r);
	}
	
	node(int _s,int _e){
		s=_s;e=_e;
		v.resize(4*(e-s+1));
		lz.resize(4*(e-s+1),0);
		ranges.resize(e-s+1);
		init(0,s,e);
	}
	
	void ppo(int i,int l,int r){
		v[i].fi+=lz[i];
		if(l!=r){
			lz[2*i+1]+=lz[i];
			lz[2*i+2]+=lz[i];
		}
		lz[i]=0;
	}
	
	void up(int i,int l,int r,int x,int y,ll nv){
		if(l==x&&r==y){
			lz[i]+=nv;return;
		}
		int m=(l+r)>>1;
		if(y<=m)up(2*i+1,l,m,x,y,nv);
		else if(x>m)up(2*i+2,m+1,r,x,y,nv);
		else{
			up(2*i+1,l,m,x,m,nv);
			up(2*i+2,m+1,r,m+1,y,nv);
		}
		ppo(2*i+1,l,m);ppo(2*i+2,m+1,r);
		v[i]=max(v[2*i+1],v[2*i+2]);
	}
	
	void up(int x,int y,ll nv){
		up(0,s,e,x,y,nv);
	}
	
	void print(int i,int l,int r){
		int m=(l+r)>>1;
		if(l!=r)print(2*i+1,l,m),print(2*i+2,m+1,r);
	}
	
	ll qry(){
		ans=v[0].fi+lz[0];
		int i=v[0].se;
		up(ranges[i].fi,ranges[i].se,-LINF);
		if(v[0].fi+lz[0]>=0)ans+=v[0].fi+lz[0];
		up(ranges[i].fi,ranges[i].se,LINF);
		return ans;
	}
	
}*root[maxn];

int n,q,sub[maxn];ll w;
bool mark[maxn];
vii AL[maxn];
vector<edge> edges;

vector<int> nodes;

void find_sz(int u,int p){
	nodes.pb(u);
	sub[u]=1;
	for(auto[v,i]:AL[u]){
		if(mark[v]||v==p)continue;
		find_sz(v,u);
		sub[u]+=sub[v];
	}
}

int cnt;
vii ranges;

ii dfs(int u,int p,int c){
	ii range={cnt,cnt};++cnt;
	for(auto[v,i]:AL[u]){
		if(mark[v]||v==p)continue;
		ii res=dfs(v,u,c);
		edges[i].comp.pb(c);
		edges[i].range.pb(res);
		mxto(range.se,res.se);
		if(p==-1)ranges.pb(res);
	}
	return range;
}

void decomp(int u){
	nodes.clear();
	find_sz(u,-1);
	int c=u;
	for(int x:nodes){
		int big=sub[u]-sub[x];
		for(auto[v,i]:AL[x]){
			if(mark[v])continue;
			if(sub[v]<sub[x])mxto(big,sub[v]);
		}
		if(2*big<=sub[u]){
			c=x;break;
		}
	}
	
	cnt=0;
	ranges.clear();
	
	dfs(c,-1,c);
	
	root[c]=new node(0,cnt-1);
	
	for(int i=0;i<sz(ranges);++i){
		for(int j=ranges[i].fi;j<=ranges[i].se;++j){
			root[c]->ranges[j]=ranges[i];
		}
	}
	
	mark[c]=true;
	for(auto[v,i]:AL[c]){
		if(!mark[v])decomp(v);
	}
}

int main(){
	sf("%d%d%lld",&n,&q,&w);
	for(int i=0;i<n-1;++i){
		int a,b;ll c;
		sf("%d%d%lld",&a,&b,&c);
		AL[a].pb({b,i});
		AL[b].pb({a,i});
		edges.pb({a,b,c,{},{}});
	}
	
	decomp(1);
	
	for(edge &e:edges){
		for(int i=0;i<sz(e.comp);++i){
			ii rng=e.range[i];
			root[e.comp[i]]->up(rng.fi,rng.se,e.w);
		}
	}
	
	set<li> s;
	for(int i=1;i<=n;++i){
		s.insert({root[i]->qry(),i});
	}
	
	ll ans=0;
	while(q--){
		ll idx,nw;
		sf("%lld%lld",&idx,&nw);
		idx=(idx+ans)%(n-1);
		nw=(nw+ans)%w;
		edge &e=edges[idx];
		ll ow=e.w;
		e.w=nw;
		
		for(int i=0;i<sz(e.comp);++i){
			ii rng=e.range[i];
			int c=e.comp[i];
			
			ll old=root[c]->ans;
			root[c]->up(rng.fi,rng.se,nw-ow);
			ll upd=root[c]->qry();
			s.erase(s.find({old,c}));
			s.insert({upd,c});
		}
		
		ans=(*--s.end()).fi;
		
		pf("%lld\n",ans);
	}
}

Compilation message (stderr)

diameter.cpp: In function 'int main()':
diameter.cpp:201:4: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  201 |  sf("%d%d%lld",&n,&q,&w);
      |    ^
diameter.cpp:204:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  204 |   sf("%d%d%lld",&a,&b,&c);
      |     ^
diameter.cpp:227:5: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  227 |   sf("%lld%lld",&idx,&nw);
      |     ^

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 7 / 7
• Subtask 4: 18 / 18
• Subtask 5: 24 / 24
• Subtask 6: 27 / 27