Submission #330497

#	Time	Username	Problem	Language	Result	Execution time	Memory
330497		AmineWeslati	Fireworks (APIO16_fireworks)	C++14	26 / 100	171 ms	8300 KiB

fireworks

//Never stop trying
#ifndef LOCAL
#pragma GCC target ("avx2")
#pragma GCC optimize ("Ofast")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#endif
#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<str> vs;
typedef vector<ld> vd;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX =3e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());

ll random(ll a, ll b){
    return a + rng() % (b - a + 1);
}

#ifndef LOCAL  
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl; 
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

int N,M; 
int P[MX],C[MX];
vi adj[MX];

bool sub1(){
	if(N!=1) return false;
	return true;
}

ll memo[305][305];

ll solve(int u, int p, int x){
	if(sz(adj[u])==1) return abs(x-C[u]);
	if(memo[u][x]!=-1) return memo[u][x];
	ll ans=INF;
	FOR(i,0,x+1){
		ll cur=abs(x-i-C[u]);
		for(auto v: adj[u]) if(v!=p) 
			cur+=solve(v,u,i);
		ckmin(ans,cur);	
	}
	return memo[u][x]=ans;
}

int main() {
    boost; IO();
    memset(memo,-1,sizeof(memo));

    cin>>N>>M; 
    FOR(i,2,N+M+1){
    	cin>>P[i]>>C[i];
    	adj[P[i]].pb(i);
    	adj[i].pb(P[i]);
    }

    if(sub1()){
    	vi vec;
    	FOR(i,2,N+M+1){
    		vec.pb(C[i]);
    	}
    	sort(all(vec));
    	int x=vec[sz(vec)/2];
    	ll ans=0;
    	for(auto xx: vec) ans+=abs(x-xx);
    	cout << ans << endl;
    }
    else{
    	ll ans=INF;
	    FOR(i,0,305){
	    	ll cur=0;
	    	for(auto u: adj[1]) cur+=solve(u,1,i);
	    	ckmin(ans,cur);
		}
	    cout << ans << endl;
    }
    


    return 0;
}

/* Careful!!!
    .Array bounds
    .Infinite loops
    .Uninitialized variables / empty containers
    .Multisets are shit

   Some insights:
    .Binary search
    .Graph representation
    .Write brute force code
    .Change your approach
*/

Compilation message (stderr)

fireworks.cpp:5: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    5 | #pragma GCC optimization ("O3")
      | 
fireworks.cpp:6: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    6 | #pragma GCC optimization ("unroll-loops")
      |

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