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

#define I_2D(row, col, width) ((row) * (width) + (col))
#define PRINT_ARR(arr, n)                                                      \
  do {                                                                         \
    for (int i = 0; i < n; i++) {                                              \
      cout << arr[i] << " ";                                                   \
    }                                                                          \
    cout << "\n";                                                              \
  } while (0)
#define PRINT_VEC_ARR(v, n)                                                    \
  do {                                                                         \
    for (int i = 0; i < n; i++) {                                              \
      cout << i << ": ";                                                       \
      for (auto item : v[i]) {                                                 \
        cout << item << " ";                                                   \
      }                                                                        \
      cout << endl;                                                            \
    }                                                                          \
  } while (0)

typedef long long ll;
typedef pair<pair<ll, ll>, ll> pp;
#define CURR(x) ((x).first.first)
#define PREV(x) ((x).first.second)
#define LEN(x) ((x).second)

#define N 1001

ll dist[N][N];
ll mmin = LONG_LONG_MAX, mmin_index = 0;
// bool visited[N];

void bfs(int j, vector<ll> *edges, ll n) {
  queue<pp> q;
  vector<bool> v(n, false);
  q.push({{j, -1}, 0});
  pp curr;
  ll s = 0;
  while (!q.empty()) {
    curr = q.front();
    q.pop();
    if (v[CURR(curr)])
      continue;
    v[CURR(curr)] = true;
    for (auto edge : edges[CURR(curr)]) {
      if (dist[j][edge])
        continue;
      if (dist[CURR(curr)][edge]) {
        dist[j][edge] = dist[CURR(curr)][edge] + LEN(curr);
        q.push({{edge, CURR(curr)}, LEN(curr) + 1});
        s += dist[j][edge];
        continue;
      }
      dist[j][edge] = LEN(curr) + 1;
      q.push({{edge, CURR(curr)}, LEN(curr) + 1});
      s += dist[j][edge];
    }
  }
  if (s < mmin) {
    mmin = s;
    mmin_index = j;
  }
}

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

  int n, m;
  cin >> n >> m;

  vector<ll> edges[n];

  int a, b;
  for (int i = 0; i < m; i++) {
    cin >> a >> b;
    a--;
    b--;
    edges[a].push_back(b);
    edges[b].push_back(a);
  }
  // PRINT_VEC_ARR(edges, n);
  for (int i = 0; i < n; i++) {
    bfs(i, edges, n);
  }
  // bfs(0, edges, n);

  cout << mmin_index + 1 << endl;
  return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

Test 46

Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: ACCEPTED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

Test 52

Verdict: ACCEPTED

Test 53

Verdict: ACCEPTED

Test 54

Verdict: ACCEPTED

Test 55

Verdict: ACCEPTED

Test 56

Verdict: ACCEPTED

Test 57

Verdict: ACCEPTED

Test 58

Verdict: ACCEPTED

Test 59

Verdict: ACCEPTED

Test 60

Verdict: ACCEPTED

Test 61

Verdict: ACCEPTED

Test 62

Verdict: ACCEPTED

Test 63

Verdict: ACCEPTED

Test 64

Verdict: ACCEPTED

Test 65

Verdict: ACCEPTED

Test 66

Verdict: ACCEPTED

Test 67

Verdict: ACCEPTED

Test 68

Verdict: ACCEPTED

Test 69

Verdict: ACCEPTED