Submission #851467

#	Time	Username	Problem	Language	Result	Execution time	Memory
851467		MilosMilutinovic	Harbingers (CEOI09_harbingers)	C++17	100 / 100	111 ms	19104 KiB

harbingers

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> B;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=100100;
const ll inf=1e9+10;

int n,s[N],w[N],tsz;
ll dep[N],dp[N];
vector<PII> g[N];

struct line {
	ll k,n;
	line(ll _k=0LL,ll _n=0LL) : k(_k),n(_n) {}
	ll calc(ll x) { return k*x+n; }
};
line stk[N];

struct op {
	int tsz;
	line ln;
};
stack<op> ops;

ll inter(line a,line b) {
	/* x=(b.n-a.n)/(a.k-b.k); */
	return (b.n-a.n)/(a.k-b.k);
}

pair<ll,ll> getrng(int idx) {
	ll L=(idx==1?-inf:inter(stk[idx-1],stk[idx]));
	if (idx>1) {
		while (stk[idx-1].calc(L)<stk[idx].calc(L)) {
			L+=1;
		}
	}
	ll R=(idx==tsz?inf:inter(stk[idx],stk[idx+1]));
	if (idx<tsz) {
		while (stk[idx+1].calc(R+1)>=stk[idx].calc(R+1)) {
			R+=1;
		}
	}
	return mp(L,R);
}

void ins(line ln) {
	if (stk[tsz].calc(inf)<ln.calc(inf)) {
		ops.push({-1,line(0ll,0ll)});
		return;
	}
	int low=1,high=tsz,pos=1;
	while (low<=high) {
		int mid=low+high>>1;
		pair<ll,ll> rng=getrng(mid);
		if (stk[mid].calc(rng.se)<ln.calc(rng.se)) {
			low=mid+1;
		} else {
			if (stk[mid].calc(rng.fi)<ln.calc(rng.fi)) {
				pos=mid+1;
				break;
			} else {
				pos=mid;
				high=mid-1;
			}
		}
	}
	ops.push({tsz,stk[pos]});
	tsz=pos;
	stk[pos]=ln;
}

void rem() {
	if (ops.top().tsz==-1) {
		tsz--;
		ops.pop();
		return;
	}
	stk[tsz]=ops.top().ln;
	tsz=ops.top().tsz;
	ops.pop();
}

ll query(ll x) {
	int low=1,high=tsz-1,pos=tsz;
	while (low<=high) {
		int mid=low+high>>1;
		pair<ll,ll> rng=getrng(mid);
		if (rng.fi<=x&&x<=rng.se) {
			pos=mid;
			break;
		}
		if (x>rng.se) {
			low=mid+1;
		} else {
			high=mid-1;
		}
	}
	return stk[pos].calc(x);
}

void dfs(int v,int pv) {
	if (v>1) {
		dp[v]=query(w[v])+dep[v]*1ll*w[v]+s[v];
	}
	ins(line(-dep[v],dp[v]));
	for (auto& e:g[v]) {
		int u=e.fi,l=e.se;
		if (u==pv) {
			continue;
		}
		dep[u]=dep[v]+l;
		dfs(u,v);
	}
	rem();
}

int main() {
	scanf("%d",&n);
	rep(i,1,n) {
		int u,v,d;
		scanf("%d%d%d",&u,&v,&d);
		g[u].pb(mp(v,d));
		g[v].pb(mp(u,d));
	}
	rep(i,2,n+1) {
		scanf("%d%d",s+i,w+i);
	}
	dfs(1,0);
	rep(i,2,n+1) printf("%lld ",dp[i]);
}

Compilation message (stderr)

harbingers.cpp: In function 'void ins(line)':
harbingers.cpp:72:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   72 |   int mid=low+high>>1;
      |           ~~~^~~~~
harbingers.cpp: In function 'll query(ll)':
harbingers.cpp:105:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  105 |   int mid=low+high>>1;
      |           ~~~^~~~~
harbingers.cpp: In function 'int main()':
harbingers.cpp:137:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  137 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
harbingers.cpp:140:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  140 |   scanf("%d%d%d",&u,&v,&d);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~
harbingers.cpp:145:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
  145 |   scanf("%d%d",s+i,w+i);
      |   ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100