Submission #619913

#	Time	Username	Problem	Language	Result	Execution time	Memory
619913		PoonYaPat	Hotspot (NOI17_hotspot)	C++14	100 / 100	1553 ms	338468 KiB

hotspot

#include <bits/stdc++.h>
using namespace std;

int n,m,k,d[5001][5001],ans_node,x[2001],y[2001];
vector<int> adj[5001];
queue<int> q;
long double ans,cnt[5001][5001];

void bfs(int x) {
    memset(d[x],0x3f,sizeof(d[x]));

    q.push(x);
    d[x][x]=0;
    cnt[x][x]=1;

    while (!q.empty()) {
        int a=q.front();
        q.pop();

        for (auto s : adj[a]) {
            if (d[x][s]>d[x][a]+1) {
                d[x][s]=d[x][a]+1;
                cnt[x][s]+=cnt[x][a];
                q.push(s);
            } else if (d[x][s]==d[x][a]+1) cnt[x][s]+=cnt[x][a];
        }
    }
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin>>n>>m;
    for (int i=0; i<m; ++i) {
        int a,b;
        cin>>a>>b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    cin>>k;
    for (int i=0; i<k; ++i) cin>>x[i]>>y[i];
    for (int i=0; i<n; ++i) bfs(i);
    for (int i=0; i<n; ++i) {
        long double sum=0;
        for (int j=0; j<k; ++j) {
            if (d[x[j]][i]+d[i][y[j]]==d[x[j]][y[j]]) {
                sum+=(cnt[x[j]][i]*cnt[i][y[j]])/cnt[x[j]][y[j]];
            }
        }
        if (sum>ans) ans_node=i,ans=sum;
    }
    cout<<ans_node;
}

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