Submission #647909

#	Time	Username	Problem	Language	Result	Execution time	Memory
647909		ghostwriter	Power Plant (JOI20_power)	C++14	100 / 100	184 ms	41152 KiB

power

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const int oo = 1e9;
const int N = 2e5 + 1;
int n, s[N], d[N][2];
vi adj[N];
void dfs(int u, int p) {
	int s0 = 0, s1 = 0;
	vi adjn;
	EACH(v, adj[u]) {
		if (v == p) continue;
		dfs(v, u);
		adjn.pb(v);
		s0 += d[v][0];
		s1 += d[v][1];
	}
	vi a;
	if (s[u]) d[u][0] = max(d[u][0], 1);
	EACH(v, adjn) {
		d[u][0] = max(d[u][0], d[v][0]);
		if (s[u]) d[u][0] = max(d[u][0], d[v][1] + 1);
		a.pb(d[v][1]);
	}
	if (sz(a) > 1) {
		sort(all(a), greater<int>());
		int cur = a[0] + a[1];
		d[u][0] = max(d[u][0], cur - s[u]);
		FOR(i, 2, sz(a) - 1) {
			cur += a[i];
			d[u][0] = max(d[u][0], cur - s[u]);
		}
	}
	if (s[u]) d[u][1] = max(d[u][1], 1);
	d[u][1] = max(d[u][1], s1 - s[u]);
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    cin >> n;
    FOR(i, 1, n - 1) {
    	int a, b;
    	cin >> a >> b;
    	adj[a].pb(b);
    	adj[b].pb(a);
    }
    FOR(i, 1, n) {
    	char c;
    	cin >> c;
    	s[i] = c - '0';
    }
    dfs(1, 0);
    cout << d[1][0];
    return 0;
}
/*
6
2 3
4 3
1 3
3 5
6 2
110011
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

Compilation message (stderr)

power.cpp: In function 'void dfs(int, int)':
power.cpp:36:31: warning: unnecessary parentheses in declaration of 'v' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
power.cpp:58:2: note: in expansion of macro 'EACH'
   58 |  EACH(v, adj[u]) {
      |  ^~~~
power.cpp:36:31: warning: unnecessary parentheses in declaration of 'v' [-Wparentheses]
   36 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
power.cpp:67:2: note: in expansion of macro 'EACH'
   67 |  EACH(v, adjn) {
      |  ^~~~
power.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
power.cpp:76:3: note: in expansion of macro 'FOR'
   76 |   FOR(i, 2, sz(a) - 1) {
      |   ^~~
power.cpp: In function 'int main()':
power.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
power.cpp:89:5: note: in expansion of macro 'FOR'
   89 |     FOR(i, 1, n - 1) {
      |     ^~~
power.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
power.cpp:95:5: note: in expansion of macro 'FOR'
   95 |     FOR(i, 1, n) {
      |     ^~~

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 53 / 53