Submission #1058990

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Source Code Expand

#include <algorithm>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <vector>

#define FOR(i,k,n) for (int (i)=(k); (i)<(n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define all(v) begin(v), end(v)
#define debug(x) cerr<< #x <<": "<<x<<endl
#define debug2(x,y) cerr<< #x <<": "<< x <<", "<< #y <<": "<< y <<endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
typedef vector<ll> vll;
typedef vector<vector<ll> > vvll;
template<class T> using vv=vector<vector< T > >;

int n, k;
vll a, b;

pii bs(ll mid) {
  pii ret = {0, 0};
  rep (i, n) {
    bool flag = (mid % a[i] == 0) ? true : false;
    ll r = mid / a[i];
    int ub = upper_bound(all(b), r) - begin(b);
    if (flag) {
      ret.first += lower_bound(all(b), r) - begin(b);
    } else {
      ret.first += ub;
    }
    ret.second += ub;
  }
  return ret;
}

int main() {
  scanf("%d %d", &n, &k);
  a.resize(n);
  b.resize(n);
  rep (i, n) {
    scanf("%lld", &a[i]);
  }
  rep (i, n) {
    scanf("%lld", &b[i]);
  }
  sort(all(a)); sort(all(b));
  ll l = a[0] * b[0] - 1;
  ll h = a[n-1] * b[n-1] + 1;
  ll mid;
  while (true) {
    mid = (l + h)/2;
    pii p = bs(mid);
    if (k <= p.first) {
      h = mid;
      continue;
    } else if (p.second < k) {
      l = mid;
      continue;
    }
    // p.first < k && k <= p.second
    break;
  }
  printf("%lld\n", mid);

  return 0;
}

Submission Info

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