Submission #646117

#	Time	Username	Problem	Language	Result	Execution time	Memory
646117		ghostwriter	Building 4 (JOI20_building4)	C++14	0 / 100	3 ms	4320 KiB

building4

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#else
#define debug(...)
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
struct Building {
	int a, b;
	bool rev;
	Building() {}
	Building(int a, int b, bool rev) : a(a), b(b), rev(rev) {}
};
const int N = 1e6 + 1;
int n, a[N], b[N], stat[N], cnt0 = 0, cnt1 = 0;
Building a1[N];
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    cin >> n;
    FOR(i, 1, 2 * n) cin >> a[i];
    FOR(i, 1, 2 * n) cin >> b[i];
    memset(stat, -1, sizeof stat);
    FOR(i, 1, 2 * n) {
    	bool rev = 0;
    	if (a[i] < b[i]) {
    		swap(a[i], b[i]);
    		rev = 1;
    	}
    	a1[i] = Building(a[i], b[i], rev);
    }
    FOS(i, 2 * n, 2) {
    	Building &pre = a1[i - 1], &cur = a1[i];
    	if (cur.a >= pre.a && cur.b >= pre.a) continue;
    	if (cur.a >= pre.a) {
    		if (cur.b >= pre.b) {
    			if (stat[i] != -1 && stat[i] != cur.rev) stat[i - 1] = pre.rev ^ 1;
				// debug(i, stat[i], cur.rev ^ 1);
    			continue;
    		}
    		bool nstat = cur.rev;
    		if (stat[i] != -1 && stat[i] != nstat) {
    			cout << -1;
    			return 0;
    		}
    		stat[i] = nstat;
    		int pos = i + 1;
    		WHILE(pos <= 2 * n && stat[pos] == -1) {
		    	Building &pre = a1[pos - 1], &cur = a1[pos];
		    	if (cur.a >= pre.a && cur.b < pre.a && cur.b >= pre.b && stat[pos - 1] == pre.rev) {
		    		stat[pos] = cur.rev;
		    		++pos;
		    	}
		    	else break;
    		}
    		continue;
    	}
    	if (cur.a >= pre.b) {
    		if (cur.b < pre.b) {
	    		bool nstat = cur.rev;
	    		if (stat[i] != -1 && stat[i] != nstat) {
	    			cout << -1;
	    			return 0;
	    		}
	    		stat[i] = nstat;
	    		int pos = i + 1;
	    		WHILE(pos <= 2 * n && stat[pos] == -1) {
			    	Building &pre = a1[pos - 1], &cur = a1[pos];
			    	if (cur.a >= pre.a && cur.b < pre.a && cur.b >= pre.b && stat[pos - 1] == pre.rev) {
			    		stat[pos] = cur.rev;
			    		++pos;
			    	}
			    	else break;
	    		}
	    		nstat = pre.rev ^ 1;
	    		stat[i - 1] = nstat;
	    		continue;
    		}
	    	bool nstat = pre.rev ^ 1;
			stat[i - 1] = nstat;
			continue;
    	}
    	cout << -1;
    	return 0;
    }
    // FOR(i, 1, 2 * n) {
    // 	cerr << stat[i] << ' ';
    // }
    // cerr << '\n';
    FOR(i, 1, 2 * n)
    	if (stat[i] == 0) ++cnt0;
    	else if (stat[i] == 1) ++cnt1;
    if (cnt0 > n || cnt1 > n) {
    	cout << -1;
    	return 0;
    }
    FOR(i, 1, 2 * n) {
    	if (stat[i] != -1) continue;
    	cnt0 += (a1[i].rev? 0 : 1);
    }
    FOR(i, 1, 2 * n) {
    	if (stat[i] != -1) continue;
    	if (cnt0 < n) {
    		if (!a1[i].rev) continue;
    		stat[i] = 0;
    		++cnt0;
    	}
    	else if (cnt0 > n) {
    		if (a1[i].rev) continue;
    		stat[i] = 1;
    		--cnt0;
    	}
    	else stat[i] = a1[i].rev;
    }
    FOR(i, 1, 2 * n) cout << (stat[i]? 'B' : 'A');
    return 0;
}
/*
2
2 10 1 5
5 2 2 3
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:65:5: note: in expansion of macro 'FOR'
   65 |     FOR(i, 1, 2 * n) cin >> a[i];
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:66:5: note: in expansion of macro 'FOR'
   66 |     FOR(i, 1, 2 * n) cin >> b[i];
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:68:5: note: in expansion of macro 'FOR'
   68 |     FOR(i, 1, 2 * n) {
      |     ^~~
building4.cpp:33:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   33 | #define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
      |                               ^
building4.cpp:76:5: note: in expansion of macro 'FOS'
   76 |     FOS(i, 2 * n, 2) {
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:134:5: note: in expansion of macro 'FOR'
  134 |     FOR(i, 1, 2 * n)
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:141:5: note: in expansion of macro 'FOR'
  141 |     FOR(i, 1, 2 * n) {
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:145:5: note: in expansion of macro 'FOR'
  145 |     FOR(i, 1, 2 * n) {
      |     ^~~
building4.cpp:32:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   32 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
building4.cpp:159:5: note: in expansion of macro 'FOR'
  159 |     FOR(i, 1, 2 * n) cout << (stat[i]? 'B' : 'A');
      |     ^~~

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