Submission #793185

#	Time	Username	Problem	Language	Result	Execution time	Memory
793185		ToniB	Fireworks (APIO16_fireworks)	C++17	19 / 100	85 ms	1488 KiB

fireworks

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 505;

int n, m, L[MAXN], R[MAXN];
vector<pair<int, int> > adj[MAXN];
ll walk[MAXN], dp[MAXN][MAXN];

void precalc(int node){
	for(pair<int, int> x : adj[node]){
		walk[x.first] = walk[node] + x.second;
		precalc(x.first);
	}
}

void dfs(int node){
	if(node >= n){
		for(int i = 0; i < MAXN; ++i) dp[node][i] = 1e9;
		dp[node][walk[node]] = 0;
	}
	for(pair<int, int> x : adj[node]){
		dfs(x.first);
		for(int i = 0; i < MAXN; ++i){
			ll mini = 1e9;
			for(int j = 0; j < MAXN; ++j){
				if(x.second + i - j >= 0) mini = min(mini, dp[x.first][j] + abs(i - j));
			}
			dp[node][i] += mini;
		}
	}
}

int main(){
	cin >> n >> m;
	for(int i = 1; i < n + m; ++i){
		int p, c;
		cin >> p >> c, --p;
		adj[p].push_back({i, c});
	}
	precalc(0);

	dfs(0);
	ll ans = 1e9;
	for(int i = 0; i < MAXN; ++i) ans = min(ans, dp[0][i]);
	for(int i = 0; i < MAXN; ++i){
		if(dp[0][i] == ans){
			for(int j = 0; j < i; ++j) assert(dp[0][j] >= dp[0][j + 1]);
			for(int j = i; j < n - 1; ++j) assert(dp[0][j] <= dp[0][j + 1]);
		}
	}
	cout << ans;
	return 0;
}

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