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Submission #1047419

# Submission time Handle Problem Language Result Execution time Memory
1047419 2024-08-07T12:46:16 Z sofijavelkovska Event Hopping (BOI22_events) C++17
10 / 100
 1500 ms 9044 KB 
#include <bits/stdc++.h>
using namespace std;

const int MAXN=(1<<18), INF=1e9;

int n;
int l[MAXN], r[MAXN];
int tree[2*MAXN-1];

bool rcompare(int x, int y)
{
    if (r[x]==r[y])
        return l[x]<l[y];

    return r[x]<r[y];
}

int find(int x, int l, int r, int lt, int rt)
{
    if (l>=rt || r<=lt)
        return INF;
    if (l>=lt && r<=rt)
        return tree[x];

    return min(find(2*x+1, l, (l+r)/2, lt, rt), find(2*x+2, (l+r)/2, r, lt, rt));
}

void update(int x, int l, int r, int index, int value)
{
    if (l>index || r<=index)
        return;
    if (r-l==1)
    {
        tree[x]=min(tree[x], value);
        return;
    }
    update(2*x+1, l, (l+r)/2, index, value);
    update(2*x+2, (l+r)/2, r, index, value);
    tree[x]=min(tree[2*x+1], tree[2*x+2]);

    return;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int q;
    cin >> n >> q;
    for (int i=0; i<n; i++)
        cin >> l[i] >> r[i];
    int sorted[n];
    for (int i=0; i<n; i++)
        sorted[i]=i;
    sort(sorted, sorted+n, rcompare);
    int ranked[n];
    for (int i=0; i<n; i++)
        ranked[sorted[i]]=i;
    map<int, int> compress;
    for (int i=0; i<n; i++)
    {
        compress[l[i]]=0;
        compress[r[i]]=0;
    }
    int counter=0;
    for (auto x : compress)
    {
        compress[x.first]=counter;
        counter=counter+1;
    }
    while (q--)
    {
        int x, y;
        cin >> x >> y;
        x=x-1;
        y=y-1;
        if (x==y)
        {
            cout << 0 << '\n';
            continue;
        }
        if (r[x]>r[y])
        {
            cout << "impossible" << '\n';
            continue;
        }
        if (r[x]==r[y])
        {
            cout << 1 << '\n';
            continue;
        }
        for (int i=0; i<2*MAXN-1; i++)
            tree[i]=INF;
        int dp[n];
        dp[ranked[y]]=0;
        update(0, 0, MAXN, compress[l[y]], 0);
        for (int i=ranked[y]-1; i>=0; i--)
        {
            dp[i]=min(INF, find(0, 0, MAXN, 0, compress[r[sorted[i]]]+1)+1);
            //cout << "l r " << l[sorted[i]] << ' ' << r[sorted[i]] << '\n';
            //cout << "find " << find(0, 0, MAXN, 0, compress[r[sorted[i]]]+1) << '\n';
            update(0, 0, MAXN, compress[l[sorted[i]]], dp[i]);
            //cout << "dp " << dp[i] << '\n';
        }
        if (dp[ranked[x]]!=INF)
            cout << dp[ranked[x]] << '\n';
        else
            cout << "impossible" << '\n';
    }

    return 0;
}



/*#include <bits/stdc++.h>
using namespace std;

const int MAXN=1e5, LOG=17;

int n;
int l[MAXN], r[MAXN];

bool rcompare(int x, int y)
{
    if (r[x]<r[y])
        return true;

    return false;
}

bool lcompare(int x, int y)
{
    if (l[x]<l[y])
        return true;

    return false;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int q;
    cin >> n >> q;
    for (int i=0; i<n; i++)
        cin >> l[i] >> r[i];
    int sorted[n];
    for (int i=0; i<n; i++)
        sorted[i]=i;
    sort(sorted, sorted+n, rcompare);
    int ranked[n];
    for (int i=0; i<n; i++)
        ranked[sorted[i]]=i;
    int lsorted[n];
    for (int i=0; i<n; i++)
        lsorted[i]=i;
    sort(lsorted, lsorted+n, lcompare);
    int t=n-1;
    set<int> farthest;
    for (int i=0; i<n; i++)
        farthest.insert(i);
    int blift[n][LOG];
    for (int i=0; i<n; i++)
        for (int j=0; j<LOG; j++)
            blift[i][j]=-1;
    for (int i=n-1; i>=0; i--)
    {
        while (t>=0 && l[lsorted[t]]>r[sorted[i]])
        {
            farthest.erase(ranked[lsorted[t]]);
            t=t-1;
        }
        auto it=farthest.end();
        it--;
        if (*it!=i)
            blift[i][0]=*it;
    }
    for (int j=1; j<LOG; j++)
        for (int i=0; i<n; i++)
            if (blift[i][j-1]!=-1 && blift[blift[i][j-1]][j-1]!=-1)
                blift[i][j]=blift[blift[i][j-1]][j-1];
    while (q--)
    {
        int x, y;
        cin >> x >> y;
        x=ranked[x-1];
        y=ranked[y-1];
        if (x>y)
        {
            cout << "impossible" << '\n';
            continue;
        }
        if (x==y)
        {
            cout << 0 << '\n';
            continue;
        }
        int total=0;
        for (int j=LOG-1; j>=0; j--)
        {
            if (blift[x][j]!=-1 && blift[x][j]<y)
            {
                x=blift[x][j];
                total=total+(1<<j);
            }
        }
        if (blift[x][0]>=y)
            cout << total+1 << '\n';
        else
            cout << "impossible" << '\n';
    }

    return 0;
}*/

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Execution timed out 1591 ms 8924 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2652 KB Output is correct
2 Correct 2 ms 2652 KB Output is correct
3 Correct 39 ms 2652 KB Output is correct
4 Correct 16 ms 2652 KB Output is correct
5 Correct 16 ms 2756 KB Output is correct
6 Correct 14 ms 2904 KB Output is correct
7 Correct 19 ms 2652 KB Output is correct
8 Correct 16 ms 2652 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2652 KB Output is correct
2 Correct 2 ms 2652 KB Output is correct
3 Correct 39 ms 2652 KB Output is correct
4 Correct 16 ms 2652 KB Output is correct
5 Correct 16 ms 2756 KB Output is correct
6 Correct 14 ms 2904 KB Output is correct
7 Correct 19 ms 2652 KB Output is correct
8 Correct 16 ms 2652 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct
10 Correct 0 ms 2652 KB Output is correct
11 Correct 1 ms 2652 KB Output is correct
12 Correct 39 ms 2736 KB Output is correct
13 Correct 16 ms 2652 KB Output is correct
14 Correct 16 ms 2652 KB Output is correct
15 Correct 15 ms 2748 KB Output is correct
16 Correct 19 ms 2792 KB Output is correct
17 Correct 18 ms 2652 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Execution timed out 1599 ms 2908 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2652 KB Output is correct
2 Correct 2 ms 2652 KB Output is correct
3 Correct 39 ms 2652 KB Output is correct
4 Correct 16 ms 2652 KB Output is correct
5 Correct 16 ms 2756 KB Output is correct
6 Correct 14 ms 2904 KB Output is correct
7 Correct 19 ms 2652 KB Output is correct
8 Correct 16 ms 2652 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct
10 Correct 0 ms 2648 KB Output is correct
11 Correct 1 ms 2652 KB Output is correct
12 Correct 39 ms 2652 KB Output is correct
13 Correct 16 ms 2648 KB Output is correct
14 Correct 16 ms 2652 KB Output is correct
15 Correct 15 ms 2748 KB Output is correct
16 Correct 18 ms 2800 KB Output is correct
17 Correct 16 ms 2648 KB Output is correct
18 Correct 0 ms 2392 KB Output is correct
19 Execution timed out 1600 ms 8960 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1568 ms 9044 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2648 KB Output is correct
2 Execution timed out 1591 ms 8924 KB Time limit exceeded
3 Halted 0 ms 0 KB -