oj.uz

Submission #370770

# Submission time Handle Problem Language Result Execution time Memory
370770 2021-02-24T15:03:45 Z stoyan_malinin Building 4 (JOI20_building4) C++14
100 / 100
 648 ms 162012 KB 
#include <functional>
#include <iostream>
#include <cstring>
#include <vector>
#include <deque>
#include <map>
#include <set>

using namespace std;

const int MAXN = 1e6 + 1e5 + 5;

int n;
int a[MAXN][2];

map <int, set <pair <int, int>>> chainVals;

vector <int> getGreedy()
{
    int lastVal = -1;
    vector <int> v;

    for(int i = 0;i<n;i++)
    {
        int smallInd = 0, bigInd = 1;
        if(a[i][smallInd]>a[i][bigInd]) swap(smallInd, bigInd);

        if(lastVal<=a[i][smallInd])
        {
            v.push_back(smallInd);
            lastVal = a[i][smallInd];
        }
        else if(lastVal<=a[i][bigInd])
        {
            v.push_back(bigInd);
            lastVal = a[i][bigInd];
        }
        else
        {
            return {};
        }
    }

    return v;
}

int netChange[MAXN], chain[MAXN];

void doFlip(int i, vector <int> &s)
{
    if(i==n) return;

    s[i] ^= 1;
    if(i!=n-1 && a[i][s[i]]>a[i+1][s[i+1]]) doFlip(i+1, s);
}

bool checkSol(vector <int> &s)
{
    int lastVal = -1;
    for(int i = 0;i<n;i++)
    {
        if(lastVal>a[i][s[i]]) return false;
        lastVal = a[i][s[i]];
    }

    return true;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n;n *= 2;
    for(int i = 0;i<n;i++) cin >> a[i][0];
    for(int i = 0;i<n;i++) cin >> a[i][1];

    vector <int> s = getGreedy();
    if(s.empty()==true)
    {
        cout << "-1" << '\n';
        return 0;
    }

    int aCnt = 0;
    for(int x: s) aCnt += (x==0);

    for(int i = n-1;i>=0;i--)
    {
        if((i==0 || a[i-1][s[i-1]]<=a[i][s[i]^1]) && (i==n-1 || a[i][s[i]^1]<=a[i+1][s[i+1]]))
        {
            netChange[i] = ((s[i]==0)?-1:+1);
            chain[i] = i;
        }
        else if((i==0 || a[i-1][s[i-1]]<=a[i][s[i]^1]) && (i==n-1 || a[i][s[i]^1]<=a[i+1][s[i+1]^1]) && chain[i+1]!=-1)
        {
            netChange[i] = ((s[i]==0)?-1:+1) + netChange[i+1];
            chain[i] = chain[i+1];
        }
        else
        {
            netChange[i] = 0;
            chain[i] = -1;
        }
    }

    /*
    cout << '\n';

    for(int i = 0;i<n;i++) cout << s[i] << " ";
    cout << '\n';

    for(int i = 0;i<n;i++) cout << netChange[i] << " ";
    cout << '\n';

    for(int i = 0;i<n;i++) cout << chain[i] << " ";
    cout << '\n';
    */

    for(int i = 0;i<n;i++)
    {
        if(chain[i]!=-1) chainVals[chain[i]].insert({netChange[i], i});
    }

    for(auto &item: chainVals)
    {
        if(aCnt>n/2)
        {
            auto it = item.second.begin();
            while(it!=item.second.end())
            {
                //cout << "k" << '\n';
                if(it->first<0 && aCnt + it->first >= n/2)
                {
                    aCnt += it->first;
                    doFlip(it->second, s);

                    //cout << " -> flip: " << it->second << '\n';
                    break;
                }

                it++;
            }
        }
        else if(aCnt<n/2)
        {
            auto it = prev(item.second.end());
            while(true)
            {
                if(it->first>0 && aCnt + it->first <= n/2)
                {
                    aCnt += it->first;
                    doFlip(it->second, s);

                    //cout << " -> flip: " << it->second << '\n';
                    break;
                }

                if(it==item.second.begin()) break;
                it--;
            }
        }
    }

    if(checkSol(s)==false || aCnt!=n/2)
    {
        cout << "-1" << '\n';
    }
    else
    {
        for(int x: s) cout << char('A'+x);
        cout << '\n';
    }
}

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 2 ms 492 KB Output is correct
7 Correct 2 ms 620 KB Output is correct
8 Correct 2 ms 876 KB Output is correct
9 Correct 2 ms 620 KB Output is correct
10 Correct 3 ms 620 KB Output is correct
11 Correct 2 ms 492 KB Output is correct
12 Correct 2 ms 492 KB Output is correct
13 Correct 2 ms 492 KB Output is correct
14 Correct 3 ms 1004 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 2 ms 620 KB Output is correct
17 Correct 2 ms 748 KB Output is correct
18 Correct 2 ms 492 KB Output is correct
19 Correct 2 ms 492 KB Output is correct
20 Correct 1 ms 492 KB Output is correct
21 Correct 1 ms 492 KB Output is correct
22 Correct 2 ms 1004 KB Output is correct
23 Correct 2 ms 876 KB Output is correct
24 Correct 2 ms 620 KB Output is correct
25 Correct 2 ms 492 KB Output is correct
26 Correct 2 ms 492 KB Output is correct
27 Correct 2 ms 620 KB Output is correct
28 Correct 2 ms 492 KB Output is correct
29 Correct 2 ms 620 KB Output is correct
30 Correct 2 ms 492 KB Output is correct
31 Correct 2 ms 768 KB Output is correct
32 Correct 2 ms 492 KB Output is correct
33 Correct 2 ms 568 KB Output is correct

Subtask #2
89.0 / 89.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 2 ms 492 KB Output is correct
7 Correct 2 ms 620 KB Output is correct
8 Correct 2 ms 876 KB Output is correct
9 Correct 2 ms 620 KB Output is correct
10 Correct 3 ms 620 KB Output is correct
11 Correct 2 ms 492 KB Output is correct
12 Correct 2 ms 492 KB Output is correct
13 Correct 2 ms 492 KB Output is correct
14 Correct 3 ms 1004 KB Output is correct
15 Correct 2 ms 620 KB Output is correct
16 Correct 2 ms 620 KB Output is correct
17 Correct 2 ms 748 KB Output is correct
18 Correct 2 ms 492 KB Output is correct
19 Correct 2 ms 492 KB Output is correct
20 Correct 1 ms 492 KB Output is correct
21 Correct 1 ms 492 KB Output is correct
22 Correct 2 ms 1004 KB Output is correct
23 Correct 2 ms 876 KB Output is correct
24 Correct 2 ms 620 KB Output is correct
25 Correct 2 ms 492 KB Output is correct
26 Correct 2 ms 492 KB Output is correct
27 Correct 2 ms 620 KB Output is correct
28 Correct 2 ms 492 KB Output is correct
29 Correct 2 ms 620 KB Output is correct
30 Correct 2 ms 492 KB Output is correct
31 Correct 2 ms 768 KB Output is correct
32 Correct 2 ms 492 KB Output is correct
33 Correct 2 ms 568 KB Output is correct
34 Correct 218 ms 8044 KB Output is correct
35 Correct 260 ms 19548 KB Output is correct
36 Correct 275 ms 19292 KB Output is correct
37 Correct 264 ms 19804 KB Output is correct
38 Correct 600 ms 149468 KB Output is correct
39 Correct 389 ms 74588 KB Output is correct
40 Correct 455 ms 86328 KB Output is correct
41 Correct 499 ms 64604 KB Output is correct
42 Correct 266 ms 20444 KB Output is correct
43 Correct 285 ms 21212 KB Output is correct
44 Correct 281 ms 21212 KB Output is correct
45 Correct 279 ms 21084 KB Output is correct
46 Correct 648 ms 162012 KB Output is correct
47 Correct 428 ms 79836 KB Output is correct
48 Correct 424 ms 79708 KB Output is correct
49 Correct 458 ms 86748 KB Output is correct
50 Correct 279 ms 21084 KB Output is correct
51 Correct 278 ms 21084 KB Output is correct
52 Correct 210 ms 21212 KB Output is correct
53 Correct 212 ms 21108 KB Output is correct
54 Correct 567 ms 160476 KB Output is correct
55 Correct 451 ms 126684 KB Output is correct
56 Correct 538 ms 68188 KB Output is correct
57 Correct 356 ms 44252 KB Output is correct
58 Correct 353 ms 44380 KB Output is correct
59 Correct 512 ms 67952 KB Output is correct
60 Correct 298 ms 41820 KB Output is correct
61 Correct 329 ms 44508 KB Output is correct
62 Correct 329 ms 43868 KB Output is correct
63 Correct 349 ms 44440 KB Output is correct
64 Correct 314 ms 43104 KB Output is correct
65 Correct 325 ms 44568 KB Output is correct