Submission #587479

#	Time	Username	Problem	Language	Result	Execution time	Memory
587479		NekoRolly	Hotspot (NOI17_hotspot)	C++17	100 / 100	514 ms	62156 KiB

hotspot

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 5e3+4;
const int inf = 1e9;

int n,m,k;
int dis[N][N],dp[N][N];
vector<int> adj[N];
bool vis[N];
double val[N];

void bfs(int rt,int dis[],int dp[]){ queue<int> d;
	if (vis[rt]) return;
	for (int i=0; i<n; i++) dis[i] = inf;
	dis[rt] = 0, dp[rt] = 1;
	for (d.push(rt); d.size(); d.pop()){ int u = d.front();
		for (int v : adj[u]){
			if (dis[v] == inf){
				dis[v] = dis[u] + 1; d.push(v);
			}
			if (dis[v] == dis[u] + 1) dp[v] += dp[u];
		}
	}
	vis[rt] = 1;
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	cin >> n >> m;

	for (int a,b; m; m--){ cin >> a >> b;
		adj[a].push_back(b), adj[b].push_back(a);
	}

	cin >> k;

	for (int a,b; k; k--){ cin >> a >> b;
		bfs(a, dis[a], dp[a]), bfs(b, dis[b], dp[b]);
		for (int i=0; i<n; i++) if (dis[a][i] + dis[b][i] == dis[a][b])
			val[i] += double(dp[a][i]*dp[b][i])/dp[a][b];
	}

	for (int i=1; i<n; i++) if (val[i] > val[k]) k = i;

	cout << k << "\n";
	
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 18 / 18
• Subtask 5: 26 / 26
• Subtask 6: 36 / 36