Submission #311633

#	Time	Username	Problem	Language	Result	Execution time	Memory
311633		bigg	Chase (CEOI17_chase)	C++14	100 / 100	323 ms	273400 KiB

chase

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1e5 + 10;
const int MAXK = 110;
ll dp1[MAXN][MAXK], dp2[MAXN][MAXK];
ll s[MAXN], a[MAXN];
int crum;
vector<int> grafo[MAXN];
ll ans;
void dfs(int x, int p){
	pair<ll, ll> maxi[MAXK];
	for(int i = 0; i <= crum; i++){

		maxi[i] = make_pair(0, 0);
 	}
 	dp1[x][0] = dp2[x][0] = 0;
	dp2[x][1] = s[x];
	
	
	for(int i = 0; i < grafo[x].size(); i++){
		int viz = grafo[x][i];
		if(viz == p) continue;
		dfs(viz, x);

		for(int k = 1; k <= crum; k++){
			dp1[x][k] = max(dp1[viz][k], dp1[x][k]);
			dp1[x][k] = max(dp1[x][k], dp1[viz][k-1] + s[x] - a[p]); 
			dp2[x][k] = max(dp2[viz][k], dp2[x][k]);
			dp2[x][k] = max(dp2[x][k], dp2[viz][k-1] + s[x] - a[viz]);
			ll val = dp1[viz][k];
			if(val >= maxi[k].first) swap(maxi[k].first, val);
			if(val >= maxi[k].second) swap(maxi[k].second, val);
		}
	}
	for(int i = 0; i < grafo[x].size(); i++){
		int viz = grafo[x][i];
		if(viz == p) continue;
		ans = max(ans, dp1[viz][crum-1] + s[x]);
		for(int k = 0; k <= crum; k++){
			ll loc = max(dp2[viz][k], k ? dp2[viz][k-1] + s[x] - a[viz] : 0);
			if(dp1[viz][crum-k]!= maxi[crum-k].first) ans = max(ans, loc + maxi[crum - k].first);
			else ans = max(ans, loc + maxi[crum-k].second);
		}
	}
}
int n;
int main(){
	scanf("%d %d", &n, &crum);
	if(crum == 0){
		printf("0\n" );
		return 0;
	}
	for(int i = 1; i <= n; i++) scanf("%lld", &a[i]);
	for(int i = 1; i < n; i++){
		int u, v;
		scanf("%d %d", &u, &v);
		grafo[u].push_back(v);
		grafo[v].push_back(u);
		s[u] += a[v];
		s[v] += a[u];
	}
	dfs(1, 0);
	printf("%lld\n",ans );
}

Compilation message (stderr)

chase.cpp: In function 'void dfs(int, int)':
chase.cpp:21:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for(int i = 0; i < grafo[x].size(); i++){
      |                 ~~^~~~~~~~~~~~~~~~~
chase.cpp:36:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |  for(int i = 0; i < grafo[x].size(); i++){
      |                 ~~^~~~~~~~~~~~~~~~~
chase.cpp: In function 'int main()':
chase.cpp:49:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   49 |  scanf("%d %d", &n, &crum);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~~
chase.cpp:54:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   54 |  for(int i = 1; i <= n; i++) scanf("%lld", &a[i]);
      |                              ~~~~~^~~~~~~~~~~~~~~
chase.cpp:57:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   57 |   scanf("%d %d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~~

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