Submission #133444

#	Time	Username	Problem	Language	Result	Execution time	Memory
133444		tdwn	Mag (COCI16_mag)	C++17	120 / 120	1925 ms	203996 KiB

mag

#include <bits/stdc++.h>
#define ll long long 
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 1000100;
vector<int>g[maxn];
ll arr[maxn], n;
ll result1;
ll result2;
 
ll dp[maxn][2];
 
void dfs(int node, int p) {
	if(arr[node] == 1) dp[node][0] = 1;
	if(arr[node] == 2) dp[node][1] = 1;



	vector<ll>v;

	ll max_0 = dp[node][0];
	ll max_1 = dp[node][1];

	for(int i:g[node]) {
		if(i != p) {
			dfs(i, node);

			if(arr[node] == 1) {
				if(arr[i] == 1) {
					dp[node][0] = max(dp[node][0], 1 + dp[i][0]);
					v.pb(dp[i][0]);
				}
				if(dp[i][1] != 0) dp[node][1] = max(dp[node][1], 1 + dp[i][1]);
			}
			else if(arr[node] == 2) {
				dp[node][1] = max(dp[node][1], 1 + dp[i][0]);
			}

			//cout<<"Updating "<<node<<" from "<<i<<" - "<<dp[i][0]<<" "<<dp[i][1]<<"\n";

			result2 = max(result2, max_0 + dp[i][1]);
			result2 = max(result2, max_1 + dp[i][0]);

			max_0 = max(max_0, dp[node][0]);
			max_1 = max(max_1, dp[node][1]);
		}
	}

	result1 = max(result1, dp[node][0]);
	result2 = max(result2, dp[node][1]);

	v.pb(0);
	v.pb(0);
	sort(v.rbegin(), v.rend());

	if(arr[node] == 2) {
		result2 = max(result2, v[0] + v[1] + 1);
	}
	else if(arr[node] == 1) {
		result1 = max(result1, v[0] + v[1] + 1);
	}

}
 
int main() {
	cin>>n;
	ll a, b;
	for(int i=0;i<n-1;i++) {
		cin>>a>>b;
		g[a].pb(b);
		g[b].pb(a);
	}
 
	ll minval = LLONG_MAX;
	for(int i=1;i<=n;i++) {
		cin>>arr[i];
		minval = min(minval, arr[i]);
	}
 
	if(minval != 1) {
		cout<<minval<<"/1\n";
	}
	else {
		dfs(1, -1);
		if(result2 > 2*result1) {
			cout<<"2/"<<result2<<"\n";
		}
		else {
			cout<<"1/"<<result1<<"\n";
		}
	}
}

• Subtask 1: 12 / 12
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 12 / 12
• Subtask 5: 12 / 12
• Subtask 6: 12 / 12
• Subtask 7: 12 / 12
• Subtask 8: 12 / 12
• Subtask 9: 12 / 12
• Subtask 10: 12 / 12