Submission #391896

#	Time	Username	Problem	Language	Result	Execution time	Memory
391896		parsabahrami	Chase (CEOI17_chase)	C++17	100 / 100	600 ms	487784 KiB

chase

/* There's someone in my head but it's not me */ 
#include <bits/stdc++.h>
 
using namespace std;

typedef long long int ll;
typedef pair<ll, ll> pii;
 
#define SZ(x)                       (int) x.size()
#define F                           first
#define S                           second

const int N = 1e5 + 2, K = 101;
int P[N], n, k; ll ans, M[N];
vector<int> adj[N]; pii dp[N][K], pd[N][K], idp[N][K], ipd[N][K];

void merge(ll v, ll u, ll x) {
	if (dp[v][x].S < max(dp[u][x].F, dp[u][x - 1].F + M[u] - P[v])) dp[v][x].S = max(dp[u][x].F, dp[u][x - 1].F + M[u] - P[v]), idp[v][x].S = u;
	if (dp[v][x].F < dp[v][x].S) swap(dp[v][x].F, dp[v][x].S), swap(idp[v][x].F, idp[v][x].S);
	if (pd[v][x].S < max(pd[u][x].F, pd[u][x - 1].F + M[v] - P[u])) pd[v][x].S = max(pd[u][x].F, pd[u][x - 1].F + M[v] - P[u]), ipd[v][x].S = u;
	if (pd[v][x].F < pd[v][x].S) swap(pd[v][x].F, pd[v][x].S), swap(ipd[v][x].F, ipd[v][x].S);
}

void DFS(ll v, ll p = -1) {
	pd[v][1].F = M[v]; ipd[v][1].F = v;
	for (ll u : adj[v]) {
		if (u != p) {
			DFS(u, v);
			for (ll i = 1; i < K; i++) {
				merge(v, u, i);
			}
		}
	}
	for (ll i = 0; i <= k; i++) {
		if (ipd[v][i].F == idp[v][k - i].F) ans = max({ans, pd[v][i].F + dp[v][k - i].S, pd[v][i].S + dp[v][k - i].F});
		else ans = max(ans, pd[v][i].F + dp[v][k - i].F);
	}
}

int main() {
	scanf("%d%d", &n, &k);
	for (int i = 1; i <= n; i++) 
        scanf("%d", &P[i]);
	for (int i = 1; i < n; i++) {
		int u, v; scanf("%d%d", &u, &v);
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	for (int i = 1; i <= n; i++) {
		for (int u : adj[i]) M[i] += P[u];
	}
	DFS(1);
	printf("%lld\n", ans);
    return 0;
}

Compilation message (stderr)

chase.cpp: In function 'int main()':
chase.cpp:41:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |  scanf("%d%d", &n, &k);
      |  ~~~~~^~~~~~~~~~~~~~~~
chase.cpp:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   43 |         scanf("%d", &P[i]);
      |         ~~~~~^~~~~~~~~~~~~
chase.cpp:45:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   45 |   int u, v; scanf("%d%d", &u, &v);
      |             ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30