Submission #1105351

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105351		whoknow	Hotspot (NOI17_hotspot)	C++17	38 / 100	6 ms	620 KiB

hotspot

#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define MAXN 5005
#define MAXEDGE 40005
#define ii pair<ll,int>
#define bit(i,j) ((i>>j)&1)
#define sz(i) (int)i.size()
#define endl '\n'
using namespace std;
int n, m, k;
vector<int>g[MAXN];
namespace sub1
{
double dp[MAXN];
ii d[MAXN][2];
void bfs(int st, int j)
{
    for(int i = 0; i <= n; i++)
        d[i][j] = {MAXEDGE, 0};
    queue<int>q;
    q.push(st);
    d[st][j] = {0, 1};
    while(q.empty() != 1)
    {
        int u = q.front();
        q.pop();
        for(int v : g[u])
        {
            if(d[v][j].F > d[u][j].F + 1)
            {
                d[v][j] = {d[u][j].F + 1, d[u][j].S};
                q.push(v);
            }
            else if(d[v][j].F == d[u][j].F + 1)
                d[v][j].S += d[u][j].S;
        }
    }
}
void calc(int st, int ed)
{
    queue<int>q;
    q.push(ed);
    while(q.empty() != 1)
    {
        int u = q.front();
        q.pop();
        dp[u] += (double)(1.0*d[u][0].S * d[u][1].S /d[st][1].S);
        for(int v : g[u])
            if(d[v][0].F + 1 == d[u][0].F)
                q.push(v);
    }
}
void solve()
{
    cin >> k;
    for(int i = 1; i <= k; i++)
    {
        int x, y;
        cin >> x >> y;
        bfs(x, 0);
        bfs(y, 1);
        calc(x, y);
    }
    int pos;
    double res = 0;
    for(int i = 0; i < n; i++)
        if(dp[i] >= res)
        {
            res = dp[i];
            pos = i;
        }
    cout << pos;
}
}
main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    sub1::solve();
}
/**
15 19
0 3
1 3
1 4
1 5
2 5
3 6
3 7
4 7
5 7
6 10
7 9
7 10
7 11
8 11
9 12
9 13
10 13
11 13
11 14
2
4 10
3 8


**/

Compilation message (stderr)

hotspot.cpp:77:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   77 | main()
      | ^~~~
hotspot.cpp: In function 'void sub1::solve()':
hotspot.cpp:74:13: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
   74 |     cout << pos;
      |             ^~~

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 11 / 11
• Subtask 4: 18 / 18
• Subtask 5: 0 / 26
• Subtask 6: 0 / 36