Submission #266938

#	Time	Username	Problem	Language	Result	Execution time	Memory
266938		shayan_p	Fireworks (APIO16_fireworks)	C++14	26 / 100	5 ms	5120 KiB

fireworks

// And you curse yourself for things you never done

#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;

const int maxn = 1e5 + 10, mod = 1e9 + 7;
const ll inf = 1e18 + 10;

vector<pii> v[maxn];
int n, m;

vector<ll> peb[maxn];
int infs[maxn];

void dfs(int u, int S = 0){
    if(u >= n){
	peb[u].PB(S);
	peb[u].PB(S);
	return;
    }
    for(auto [y, x] : v[u]){
	dfs(y, x);
	infs[u]+= infs[y];
	if(sz(peb[u]) < sz(peb[y]))
	    swap(peb[u], peb[y]);
	for(int x : peb[y])
	    peb[u].PB(x);
    }
    sort(peb[u].begin(), peb[u].end());
    int N = sz(peb[u]) + infs[u];
    assert(sz(peb[u]) >= (N/2)+1);
    ll L = peb[u][(N/2)-1], R = peb[u][(N/2)];
    infs[u]+= sz(peb[u]) - (N/2) - 1;
    peb[u].resize((N/2) + 1);
    peb[u].pop_back(), peb[u].pop_back();
    peb[u].PB(L + S);
    peb[u].PB(R + S);
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie();

    ll sm = 0;
    
    cin >> n >> m;
    for(int i = 1; i < n+m; i++){
	int a, b;
	cin >> a >> b;
	v[--a].PB({i, b});
	sm+= b;
    }
    dfs(0);
    sort(peb[0].begin(), peb[0].end());
    int N = sz(peb[0]) + infs[0];
    ll bst = peb[0][(N/2)-1];
    ll df = 0;
    for(ll x : peb[0]){
	df+= abs(x - bst);
	df-= x;
    }
    df+= -bst * infs[0];
    ll ans = df + sm *2;
    return cout << ans/2 << endl, 0;
}

Compilation message (stderr)

fireworks.cpp: In function 'void dfs(int, int)':
fireworks.cpp:31:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   31 |     for(auto [y, x] : v[u]){
      |              ^

• Subtask 1: 7 / 7
• Subtask 2: 19 / 19
• Subtask 3: 0 / 29
• Subtask 4: 0 / 45