Submission #212742

#	Time	Username	Problem	Language	Result	Execution time	Memory
212742		_7_7_	Building 4 (JOI20_building4)	C++14	0 / 100	8 ms	640 KiB

building4

#include <bits/stdc++.h>                                           
 
//#define int long long
//#pragma GCC optimize("Ofast")
//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")
 
 
#define file(s) freopen(s".in","r",stdin); freopen(s".out","w",stdout);
#define all(x) x.begin(), x.end()
#define sz(s) (int)s.size()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define s second
#define f first
 
 
using namespace std;
 
 
typedef pair < long long, long long > pll;    
typedef pair < int, int > pii;
typedef unsigned long long ull;         
typedef vector < pii > vpii;
typedef vector < int > vi;
typedef long double ldb;  
typedef long long ll;  
typedef double db;                             
 
 
const int dx[] = {1, -1, 0, 0}, dy[] = {0, 0, 1, -1}, block = 333;
const pii base = mp(1171, 3307), Mod = mp(1e9 + 7, 1e9 + 9);
const int inf = 1e9, maxn = 4e5 + 148, mod = 1e9 + 7, N = 1e6 + 11;
const db eps = 1e-12, pi = 3.14159265359;
const ll INF = 1e18;


int n, a[N], b[N], t[N << 2][2], f[N], l[N], r[N], res[N];

void update (int pos, int lvl, int x, int v = 1, int tl = 1, int tr = n + n) {
	if (tl == tr) {
		t[v][lvl] = x;
		return;
	}

	int tm = (tl + tr) >> 1;
	if (pos <= tm)
		update(pos, lvl, x, v << 1, tl, tm);
	else
		update(pos, lvl, x, v << 1 | 1, tm + 1, tr);

	if (!lvl)
		t[v][lvl] = min(t[v << 1][lvl], t[v << 1 | 1][lvl]);
	else
		t[v][lvl] = max(t[v << 1][lvl], t[v << 1 | 1][lvl]);	
}

int get (int l, int r, int lvl, int v = 1, int tl = 1, int tr = n + n) {
	if (l > r || tl > r || l > tr)
		return !lvl ? inf : -inf;
	
	if (l <= tl && tr <= r)
		return t[v][lvl];

	int tm = (tl + tr) >> 1;

	if (!lvl)
		return min(get(l, r, lvl, v << 1, tl, tm), get(l, r, lvl, v << 1 | 1, tm + 1, tr));

	return max(get(l, r, lvl, v << 1, tl, tm), get(l, r, lvl, v << 1 | 1, tm + 1, tr));
}

main () {
	scanf("%d", &n);
	
	for (int i = 1; i <= n + n; ++i)
		scanf("%d", &a[i]);

	for (int i = 1; i <= n + n; ++i)
		scanf("%d", &b[i]);

	for (int i = 1; i <= n + n;) {
		f[i] = i;
		int j = i + 1;
		while (j <= n + n  && a[j] >= a[j - 1]) {
			f[j] = i;
			++j;
		}
		i = j;
	}

	for (int i = 1; i <= n + n; ++i) {
		l[i] = inf, r[i] = -inf;

		if (i == 1 || (f[i - 1] == 1 && b[i] >= a[i - 1]))  //case when i is the 1st element 
			l[i] = r[i] = 0;
		
		if (i > 1 && b[i] >= b[i - 1]) {
			l[i] = min(l[i], l[i - 1]);
			r[i] = max(r[i], r[i - 1]);
		}

		if (i > 1 && b[i] >= a[i - 1]) {
			l[i] = min(l[i], get(max(1, f[i - 1] - 1), i - 2, 0));
			r[i] = max(r[i], get(max(1, f[i - 1] - 1), i - 2, 1));
		}

		if (l[i] < inf) {
			l[i]++;
			r[i]++;
		}

		if (b[i] <= a[i + 1]) {
			update(i, 0, l[i]);		
			update(i, 1, r[i]);
		} else {
			update(i, 0, inf);
			update(i, 1, -inf);
		}
	}

	int lst = -1;
	for (int i = n + n; i > 0; --i) {
		if (l[i] <= n && n <= r[i]) {
			lst = i;
			break;
		}
		if (a[i] < a[i -  1])
			break;
	}

	if (lst == -1) {
		cout << lst << endl;
		return 0;
	}

	int cur = n;
	res[lst] = 1;
	int timer = 0;
	while (--cur) {
		++timer;
		assert(lst > 1);
		if (b[lst - 1] <= b[lst] && l[lst - 1] <= cur && cur <= r[lst - 1]) {
			res[--lst] = 1;
			continue;
		}


		assert(a[lst - 1] <= b[lst]);
		if (lst == 3) {
			
		}
		while (--lst) {
			if (b[lst - 1] <= a[lst] && l[lst - 1] <= cur && cur <= r[lst - 1])
				break;
		}

		res[--lst] = 1;		
	}		

	for (int i = 1; i <= n + n; ++i) 
		printf("%c", 'A' + res[i]);	
}

Compilation message (stderr)

building4.cpp:74:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () {
       ^
building4.cpp: In function 'int main()':
building4.cpp:75:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
building4.cpp:78:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
   ~~~~~^~~~~~~~~~~~~
building4.cpp:81:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &b[i]);
   ~~~~~^~~~~~~~~~~~~

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