Submission #212195

#	Time	Username	Problem	Language	Result	Execution time	Memory
212195		mode149256	Traffic (IOI10_traffic)	C++14	100 / 100	1157 ms	155256 KiB

traffic

/*input

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

typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;

typedef vector<int> vi;
typedef vector<vi> vii;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<vl> vll;
typedef vector<pi> vpi;
typedef vector<vpi> vpii;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
typedef vector<pd> vpd;
typedef vector<bool> vb;
typedef vector<vb> vbb;
typedef std::string str;
typedef std::vector<str> vs;

#define x first
#define y second
#define debug(...) cout<<"["<<#__VA_ARGS__<<": "<<__VA_ARGS__<<"]\n"

const int MOD = 1000000007;
const ll INF = std::numeric_limits<ll>::max();
const int MX = 100101;
const ld PI = 3.14159265358979323846264338327950288419716939937510582097494L;

template<typename T>
pair<T, T> operator+(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x + b.x, a.y + b.y); }
template<typename T>
pair<T, T> operator-(const pair<T, T> &a, const pair<T, T> &b) { return pair<T, T>(a.x - b.x, a.y - b.y); }
template<typename T>
T operator*(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.x + a.y * b.y); }
template<typename T>
T operator^(const pair<T, T> &a, const pair<T, T> &b) { return (a.x * b.y - a.y * b.x); }

template<typename T>
void print(vector<T> vec, string name = "") {
	cout << name;
	for (auto u : vec)
		cout << u << ' ';
	cout << '\n';
}

vl W;
vii edges;
ll viso;
int ats = 0;
ll cur = (ll)1e16;

ll dfs(int x, int p) {
	ll dab = 0;
	ll sum = W[x];

	for (auto u : edges[x]) {
		if (u != p) {
			ll ret = dfs(u, x);
			sum += ret;
			dab = max(dab, ret);
		}
	}

	dab = max(dab, viso - sum);
	if (dab < cur) {
		cur = dab;
		ats = x;
	}
	return sum;
}

int LocateCentre(int N, int P[], int S[], int D[]) {
	W = vl(N);
	edges = vii(N);
	viso = 0;
	for (int i = 0; i < N; ++i)
	{
		W[i] = P[i];
		viso += W[i];
	}

	for (int i = 0; i < N - 1; ++i)
	{
		int a = S[i], b = D[i];
		edges[a].emplace_back(b);
		edges[b].emplace_back(a);
	}

	dfs(0, -1);
	return ats;
}

/* Look for:
* special cases (n=1?)
* overflow (ll vs int?)
* the exact constraints (multiple sets are too slow for n=10^6 :( )
* array bounds
*/

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25