oj.uz

Submission #211601

# Submission time Handle Problem Language Result Execution time Memory
211601 2020-03-20T19:14:01 Z eggag32 Building 4 (JOI20_building4) C++17
11 / 100
 2000 ms 132180 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define debug(x) cerr << #x << ": " << x << endl;
#define debug2(x, y) debug(x) debug(y);
#define repn(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(i, a) for(int i = 0; i < (int)(a); i++)
#define all(v) v.begin(), v.end() 
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define sq(x) ((x) * (x))
const int MAXN = 2100;

template<class T> T gcd(T a, T b){ return ((b == 0) ? a : gcd(b, a % b)); }

int dp[2 * MAXN][MAXN][2][2]; //[index][number of a's used][current (b is 0, a is 1)][last]

int a[2 * MAXN], b[2 * MAXN];

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	//freopen("1.in", "r", stdin);
	//freopen("output.out", "w", stdout);
	int n;
	cin >> n;
	repn(i, 1, 2 * n + 1) cin >> a[i];
	repn(i, 1, 2 * n + 1) cin >> b[i];
	rep(i, 2 * n + 1) rep(j, n + 1) rep(k, 2) rep(l, 2) dp[i][j][k][l] = 0;
	if(a[2] >= a[1]) dp[2][2][1][1] = 1;
	if(a[2] >= b[1]) dp[2][1][1][0] = 1;
	if(b[2] >= a[1]) dp[2][1][0][1] = 1;
	if(b[2] >= b[1]) dp[2][0][0][0] = 1;
	repn(i, 3, 2 * n + 1){
		rep(j, min(n + 1, i + 1)){
			int cur = i;
			int last = i - 1;
			if(a[i] >= a[i - 1]){
				if(j){
					if(dp[last][j - 1][1][1]) dp[cur][j][1][1] = 1;
					else if(dp[last][j - 1][1][0]) dp[cur][j][1][1] = 1;
				}
			}
			if(a[i] >= b[i - 1]){
				if(j){
					if(dp[last][j - 1][0][0]) dp[cur][j][1][0] = 1;
					else if(dp[last][j - 1][0][1]) dp[cur][j][1][0] = 1;
				}

			}
			if(b[i] >= a[i - 1]){
				if(dp[last][j][1][0]) dp[cur][j][0][1] = 1;
				else if(dp[last][j][1][1]) dp[cur][j][0][1] = 1;
			}
			if(b[i] >= b[i - 1]){
				if(dp[last][j][0][0]) dp[cur][j][0][0] = 1;
				else if(dp[last][j][0][1]) dp[cur][j][0][0] = 1;
			}
		}
	}
	//now we need to reconstruct the answer
	if(dp[2 * n][n][0][0]){
		string ans = "B";
		int lst = 0;
		int ind = 2 * n - 1;
		int cur = n;
		while(ans.size() != 2 * n){
			int f = 0;
			if(lst) ans += 'A', f = 1;
			else ans += 'B';
			if(dp[ind][cur][lst][0]) lst = 0;
			else if(dp[ind][cur][lst][1]) lst = 1;
			if(f) cur--;
			ind--;
		}
		reverse(all(ans));
		cout << ans << endl;
	}
	else if(dp[2 * n][n][0][1]){
		string ans = "B";
		int lst = 1;
		int ind = 2 * n - 1;
		int cur = n;
		while(ans.size() != 2 * n){
			int f = 0;
			if(lst) ans += 'A', f = 1;
			else ans += 'B';
			if(dp[ind][cur][lst][0]) lst = 0;
			else if(dp[ind][cur][lst][1]) lst = 1;
			if(f) cur--;
			ind--;
		}
		reverse(all(ans));
		cout << ans << endl;
	}
	else if(dp[2 * n][n][1][1]){
		string ans = "A";
		int lst = 1;
		int ind = 2 * n - 1;
		int cur = n - 1;
		while(ans.size() != 2 * n){
			int f = 0;
			if(lst) ans += 'A', f = 1;
			else ans += 'B';
			if(dp[ind][cur][lst][0]) lst = 0;
			else if(dp[ind][cur][lst][1]) lst = 1;
			if(f) cur--;
			ind--;
		}
		reverse(all(ans));
		cout << ans << endl;
	}
	else if(dp[2 * n][n][1][0]){
		string ans = "A";
		int lst = 0;
		int ind = 2 * n - 1;
		int cur = n - 1;
		while(ans.size() != 2 * n){
			int f = 0;
			if(lst) ans += 'A', f = 1;
			else ans += 'B';
			if(dp[ind][cur][lst][0]) lst = 0;
			else if(dp[ind][cur][lst][1]) lst = 1;
			if(f) cur--;
			ind--;
		}
		reverse(all(ans));
		cout << ans << endl;
	}
	else{
		cout << -1 << endl;
		return 0;
	}
	return 0;
}
/*
Things to look out for:
	- Integer overflows
	- Array bounds
	- Special cases
Be careful!
*/

Compilation message

building4.cpp: In function 'int main()':
building4.cpp:74:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(ans.size() != 2 * n){
         ~~~~~~~~~~~^~~~~~~~
building4.cpp:91:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(ans.size() != 2 * n){
         ~~~~~~~~~~~^~~~~~~~
building4.cpp:108:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(ans.size() != 2 * n){
         ~~~~~~~~~~~^~~~~~~~
building4.cpp:125:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(ans.size() != 2 * n){
         ~~~~~~~~~~~^~~~~~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 4 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 83 ms 121848 KB Output is correct
6 Correct 85 ms 116216 KB Output is correct
7 Correct 68 ms 92792 KB Output is correct
8 Correct 76 ms 106748 KB Output is correct
9 Correct 79 ms 111480 KB Output is correct
10 Correct 63 ms 90360 KB Output is correct
11 Correct 87 ms 123768 KB Output is correct
12 Correct 97 ms 131960 KB Output is correct
13 Correct 101 ms 131960 KB Output is correct
14 Correct 97 ms 131960 KB Output is correct
15 Correct 102 ms 131960 KB Output is correct
16 Correct 99 ms 131960 KB Output is correct
17 Correct 98 ms 131832 KB Output is correct
18 Correct 101 ms 131960 KB Output is correct
19 Correct 98 ms 131960 KB Output is correct
20 Correct 98 ms 131960 KB Output is correct
21 Correct 96 ms 131960 KB Output is correct
22 Correct 106 ms 131960 KB Output is correct
23 Correct 104 ms 132180 KB Output is correct
24 Correct 95 ms 131960 KB Output is correct
25 Correct 96 ms 131196 KB Output is correct
26 Correct 98 ms 131960 KB Output is correct
27 Correct 91 ms 131960 KB Output is correct
28 Correct 84 ms 114936 KB Output is correct
29 Correct 97 ms 131960 KB Output is correct
30 Correct 84 ms 115832 KB Output is correct
31 Correct 97 ms 131960 KB Output is correct
32 Correct 78 ms 101880 KB Output is correct
33 Correct 97 ms 131960 KB Output is correct

Subtask #2
0 / 89.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 4 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 83 ms 121848 KB Output is correct
6 Correct 85 ms 116216 KB Output is correct
7 Correct 68 ms 92792 KB Output is correct
8 Correct 76 ms 106748 KB Output is correct
9 Correct 79 ms 111480 KB Output is correct
10 Correct 63 ms 90360 KB Output is correct
11 Correct 87 ms 123768 KB Output is correct
12 Correct 97 ms 131960 KB Output is correct
13 Correct 101 ms 131960 KB Output is correct
14 Correct 97 ms 131960 KB Output is correct
15 Correct 102 ms 131960 KB Output is correct
16 Correct 99 ms 131960 KB Output is correct
17 Correct 98 ms 131832 KB Output is correct
18 Correct 101 ms 131960 KB Output is correct
19 Correct 98 ms 131960 KB Output is correct
20 Correct 98 ms 131960 KB Output is correct
21 Correct 96 ms 131960 KB Output is correct
22 Correct 106 ms 131960 KB Output is correct
23 Correct 104 ms 132180 KB Output is correct
24 Correct 95 ms 131960 KB Output is correct
25 Correct 96 ms 131196 KB Output is correct
26 Correct 98 ms 131960 KB Output is correct
27 Correct 91 ms 131960 KB Output is correct
28 Correct 84 ms 114936 KB Output is correct
29 Correct 97 ms 131960 KB Output is correct
30 Correct 84 ms 115832 KB Output is correct
31 Correct 97 ms 131960 KB Output is correct
32 Correct 78 ms 101880 KB Output is correct
33 Correct 97 ms 131960 KB Output is correct
34 Execution timed out 2092 ms 73760 KB Time limit exceeded
35 Halted 0 ms 0 KB -