oj.uz

Submission #213503

# Submission time Handle Problem Language Result Execution time Memory
213503 2020-03-26T02:50:11 Z vincent97198 Building 4 (JOI20_building4) C++14
100 / 100
 318 ms 26092 KB 
#include <bits/stdc++.h>
#define ll long long
#define N 500005

using namespace std;

struct item{
  int MIN=1e9,MAX=-1e9;
};

int n,A[N*2],B[N*2];
item dp[2*N][2];

void update(item &now,item &pre,int val)
{
    now.MIN=min(now.MIN,pre.MIN+val);
    now.MAX=max(now.MAX,pre.MAX+val);
}

bool check(item now,int val)
{
    return now.MAX>=val && now.MIN<=val;
}

void init()
{
    cin >> n;
    for(int i=0;i<2*n;++i)
        cin >> A[i];
    for(int i=0;i<2*n;++i)
        cin >> B[i];
}

void solve()
{
    dp[0][0]=item{1,1},dp[0][1]=item{0,0};
    for ( int i = 0; i < 2 * n - 1; ++i ) {
        for ( int j = 0; j < 2; ++j ) {
            if ( j == 0 && A[i + 1] >= A[i] )
                update( dp[i + 1][0], dp[i][j], 1 );
            if ( j == 1 && A[i + 1] >= B[i] )
                update( dp[i + 1][0], dp[i][j], 1 );
            if ( j == 0 && B[i + 1] >= A[i] )
                update( dp[i + 1][1], dp[i][j], 0 );
            if ( j == 1 && B[i + 1] >= B[i] )
                update( dp[i + 1][1], dp[i][j], 0 );
        }
    }

    if ( !check( dp[2 * n - 1][0], n ) && !check( dp[2 * n - 1][1], n ) ) {
        cout << -1 << endl;
        return ;
    }

    string s;
    bool pre;
    int num = n;
    A[2 * n] = B[2 * n] = 1e9;
    for ( int i = 2 * n - 1; i >= 0; --i ) {
        if ( check( dp[i][0], num ) && A[i] <= (pre ? B[i + 1] : A[i + 1]) ) {
            s += "A";
            --num;
            pre = false;
        }
        else {
            s += "B";
            pre = true;
        }
    }

    reverse( s.begin(), s.end() );

    cout << s << endl;
}

int main()
{
    ios_base::sync_with_stdio( false );
    cin.tie( nullptr );
    cout.tie( nullptr );

    init();
    solve();

    return 0;
}

Compilation message

building4.cpp: In function 'void solve()':
building4.cpp:60:53: warning: 'pre' may be used uninitialized in this function [-Wmaybe-uninitialized]
         if ( check( dp[i][0], num ) && A[i] <= (pre ? B[i + 1] : A[i + 1]) ) {
                                                ~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 6 ms 512 KB Output is correct
6 Correct 6 ms 512 KB Output is correct
7 Correct 6 ms 512 KB Output is correct
8 Correct 6 ms 512 KB Output is correct
9 Correct 6 ms 512 KB Output is correct
10 Correct 6 ms 512 KB Output is correct
11 Correct 6 ms 512 KB Output is correct
12 Correct 6 ms 512 KB Output is correct
13 Correct 6 ms 512 KB Output is correct
14 Correct 6 ms 512 KB Output is correct
15 Correct 6 ms 384 KB Output is correct
16 Correct 6 ms 512 KB Output is correct
17 Correct 6 ms 512 KB Output is correct
18 Correct 6 ms 512 KB Output is correct
19 Correct 6 ms 384 KB Output is correct
20 Correct 5 ms 512 KB Output is correct
21 Correct 5 ms 512 KB Output is correct
22 Correct 6 ms 512 KB Output is correct
23 Correct 5 ms 512 KB Output is correct
24 Correct 6 ms 512 KB Output is correct
25 Correct 6 ms 512 KB Output is correct
26 Correct 5 ms 512 KB Output is correct
27 Correct 6 ms 512 KB Output is correct
28 Correct 6 ms 512 KB Output is correct
29 Correct 6 ms 512 KB Output is correct
30 Correct 5 ms 512 KB Output is correct
31 Correct 6 ms 512 KB Output is correct
32 Correct 5 ms 512 KB Output is correct
33 Correct 6 ms 512 KB Output is correct

Subtask #2
89.0 / 89.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 6 ms 512 KB Output is correct
6 Correct 6 ms 512 KB Output is correct
7 Correct 6 ms 512 KB Output is correct
8 Correct 6 ms 512 KB Output is correct
9 Correct 6 ms 512 KB Output is correct
10 Correct 6 ms 512 KB Output is correct
11 Correct 6 ms 512 KB Output is correct
12 Correct 6 ms 512 KB Output is correct
13 Correct 6 ms 512 KB Output is correct
14 Correct 6 ms 512 KB Output is correct
15 Correct 6 ms 384 KB Output is correct
16 Correct 6 ms 512 KB Output is correct
17 Correct 6 ms 512 KB Output is correct
18 Correct 6 ms 512 KB Output is correct
19 Correct 6 ms 384 KB Output is correct
20 Correct 5 ms 512 KB Output is correct
21 Correct 5 ms 512 KB Output is correct
22 Correct 6 ms 512 KB Output is correct
23 Correct 5 ms 512 KB Output is correct
24 Correct 6 ms 512 KB Output is correct
25 Correct 6 ms 512 KB Output is correct
26 Correct 5 ms 512 KB Output is correct
27 Correct 6 ms 512 KB Output is correct
28 Correct 6 ms 512 KB Output is correct
29 Correct 6 ms 512 KB Output is correct
30 Correct 5 ms 512 KB Output is correct
31 Correct 6 ms 512 KB Output is correct
32 Correct 5 ms 512 KB Output is correct
33 Correct 6 ms 512 KB Output is correct
34 Correct 289 ms 23416 KB Output is correct
35 Correct 288 ms 24116 KB Output is correct
36 Correct 280 ms 23728 KB Output is correct
37 Correct 286 ms 24240 KB Output is correct
38 Correct 275 ms 24240 KB Output is correct
39 Correct 278 ms 24368 KB Output is correct
40 Correct 293 ms 25836 KB Output is correct
41 Correct 274 ms 24880 KB Output is correct
42 Correct 290 ms 25264 KB Output is correct
43 Correct 318 ms 25964 KB Output is correct
44 Correct 306 ms 25964 KB Output is correct
45 Correct 317 ms 25964 KB Output is correct
46 Correct 293 ms 25964 KB Output is correct
47 Correct 292 ms 25964 KB Output is correct
48 Correct 291 ms 25964 KB Output is correct
49 Correct 292 ms 25964 KB Output is correct
50 Correct 299 ms 25964 KB Output is correct
51 Correct 312 ms 25964 KB Output is correct
52 Correct 178 ms 25964 KB Output is correct
53 Correct 181 ms 26092 KB Output is correct
54 Correct 164 ms 25964 KB Output is correct
55 Correct 169 ms 25964 KB Output is correct
56 Correct 295 ms 25964 KB Output is correct
57 Correct 251 ms 25836 KB Output is correct
58 Correct 257 ms 25964 KB Output is correct
59 Correct 257 ms 25964 KB Output is correct
60 Correct 244 ms 24496 KB Output is correct
61 Correct 260 ms 25964 KB Output is correct
62 Correct 254 ms 25580 KB Output is correct
63 Correct 256 ms 25964 KB Output is correct
64 Correct 251 ms 25136 KB Output is correct
65 Correct 261 ms 25964 KB Output is correct