Submission #932602

#	Time	Username	Problem	Language	Result	Execution time	Memory
932602		AdamGS	Building 4 (JOI20_building4)	C++17	0 / 100	2 ms	4700 KiB

building4

#include<bits/stdc++.h>
using namespace std;
typedef long double ld;
typedef long long ll;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const ll LIM=1e6+7;
ll T[LIM][2], jaki[LIM], czy[LIM];
int co(int x) {
  if(jaki[x]) return -1;
  return 1;
}
int main() {
  ios_base::sync_with_stdio(0); cin.tie(0);
  ll n;
  cin >> n; n*=2;
  rep(i, n) {
    cin >> T[i][0];
    T[i][0]*=2*n;
    T[i][0]+=(ll)(2*i);
  }
  rep(i, n) {
    cin >> T[i][1];
    T[i][1]*=2*n;
    T[i][1]+=(ll)(2*i+1);
  }
  ll lst=0, sum=0;
  rep(i, n) {
    if(T[i][0]<T[i][1]) {
      if(lst<T[i][0]) {
        lst=T[i][0];
      } else if(lst<T[i][1]) {
        lst=T[i][1];
        jaki[i]=1;
      } else {
        cout << -1 << '\n';
        return 0;
      }
    } else {
      if(lst<T[i][1]) {
        lst=T[i][1];
        jaki[i]=1;
      } else if(lst<T[i][0]) {
        lst=T[i][0];
      } else {
        cout << -1 << '\n';
        return 0;
      }
    }
    sum+=co(i);
  }
  int p=n-1, bil=0;
  for(int i=n-1; i>=0; --i) {
    if(T[i][jaki[i]]>T[i][jaki[i]^1] || (i<n-1 && T[i][jaki[i]^1]>max(T[i+1][0], T[i+1][1]))) {
      p=i-1; bil=0;
      continue;
    }
    if(i==n-1 || T[i][jaki[i]^1]<T[i+1][jaki[i+1]]) {
      p=i; bil=0;
    }
    bil+=co(i);
    if(abs(sum-2*bil)<abs(sum)) {
      sum-=2*bil;
      for(int j=i; j<=p; ++j) jaki[j]^=1;
      p=i-1; bil=0;
    }
  }
  if(sum!=0) {
    cout << -1 << '\n';
    return 0;
  }
  rep(i, n) cout << (jaki[i]?"B":"A");
  cout << '\n';
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 89