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Submission #1016828

# Submission time Handle Problem Language Result Execution time Memory
1016828 2024-07-08T13:02:41 Z GrindMachine Railway Trip (JOI17_railway_trip) C++17
20 / 100
 2000 ms 16928 KB 
#include <bits/stdc++.h>
 
using namespace std ;
 
// modified from: https://oj.uz/submission/825591
 
const int MAX = 1e5 + 10 ;
 
int arr[MAX] ;
int n , k , q ;
 
int L[MAX][20] , R[MAX][20] ;
 
int solve(int x , int y)
{
    int ans = 0;
    int l = x, r = x;
 
    while(true){
        int l2 = -1, r2 = -1;
        if(arr[l] > arr[r]){
            l2 = L[l][0], r2 = R[l][0];
        }
        else if(arr[l] < arr[r]){
            l2 = L[r][0], r2 = R[r][0];
        }
        else{
            l2 = L[l][0], r2 = R[r][0];
        }
 
        // int l2 = min(L[l][0],L[r][0]);
        // int r2 = max(R[l][0],R[r][0]);
        if(r2 >= y) break;
        l = l2, r = r2;
        ans++;
    }
    
    int oldl = l, oldr = r;
    x = r;
    l = r = y;
 
    while(true){
        int l2 = min(L[l][0],L[r][0]);
        int r2 = max(R[l][0],R[r][0]);
        if(l2 <= x) break;
        l = l2, r = r2;
        ans++;
    }
    
    int cnt = 0;
    
    vector<pair<int,int>> check;
    check.push_back({oldl,l});
    check.push_back({oldl,r});
    check.push_back({oldr,l});
    check.push_back({oldr,r});

    for(auto [x,y] : check){
        if(R[x][0] == r or L[y][0] == x){
            cnt++;
        }
    }
 
    assert(cnt);
    return ans;

    // int ans = 0 ;
    // int l = x , r = x ;
    // for(int i = 19 ; i >= 0 ; --i)
    // {
    //     if(max(R[l][i] , R[r][i]) < y)
    //     {
    //         ans += (1 << i)  ;
    //         int l2 = l , r2 = r ;
    //         l = min(L[l2][i] , L[r2][i]) ;
    //         r = max(R[l2][i] , R[r2][i]) ;
    //     }
    // }
    // x = r ;
    // l = r = y ;
    // for(int i = 19 ; i >= 0 ; --i)
    // {
    //     if(min(L[l][i] , L[r][i]) > x)
    //     {
    //         ans += (1 << i) ;
    //         int l2 = l , r2 = r ;
    //         l = min(L[l2][i] , L[r2][i]) ;
    //         r = max(R[l2][i] , R[r2][i]) ;
    //     }
    // }
    // return ans ;
}
 
int main()
{
    ios_base::sync_with_stdio(0) ;
    cin.tie(0) ;
    cin>>n>>k>>q ;
    for(int i = 1 ; i <= n ; ++i)
        cin>>arr[i] ;
    stack<int>s ;
    for(int i = 1 ; i <= n ; ++i)
    {
        L[i][0] = 1 ;
        while(s.size() && arr[i] > arr[s.top()])
            s.pop() ;
        if(s.size())
            L[i][0] = s.top() ;
        s.push(i) ;
    }
    while(s.size())
        s.pop() ;
    for(int i = n ; i >= 1 ; --i)
    {
        R[i][0] = n ;
        while(s.size() && arr[i] > arr[s.top()])
            s.pop() ;
        if(s.size())
            R[i][0] = s.top() ;
        s.push(i) ;
    }
    for(int j = 1 ; j < 20 ; ++j)
    {
        for(int i = 1 ; i <= n ; ++i)
        {
            // int x = L[i][j-1], y = R[i][j-1];
            // if(arr[x] < arr[y]) swap(x,y);
            // if(arr[x] >= arr[y]){
            //     L[i][j] = L[x][j-1];
            //     R[i][j] = R[x][j-1];
            // }
            L[i][j] = min(L[L[i][j-1]][j-1] , L[R[i][j-1]][j-1]) ; 
            R[i][j] = max(R[R[i][j-1]][j-1] , R[L[i][j-1]][j-1]) ;
        }
    }
    while(q--)
    {
        int x , y ;
        cin>>x>>y ;
        if(x > y)
            swap(x , y) ;
        cout<<solve(x , y)<<"\n" ;
    }
    return 0 ;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 0 ms 2396 KB Output is correct
4 Correct 0 ms 2396 KB Output is correct
5 Correct 1 ms 2392 KB Output is correct
6 Correct 0 ms 2396 KB Output is correct
7 Correct 1 ms 2396 KB Output is correct
8 Correct 0 ms 2396 KB Output is correct
9 Correct 0 ms 2396 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2396 KB Output is correct
2 Correct 17 ms 16512 KB Output is correct
3 Correct 15 ms 16324 KB Output is correct
4 Correct 14 ms 16476 KB Output is correct
5 Correct 15 ms 16476 KB Output is correct
6 Correct 14 ms 16476 KB Output is correct
7 Correct 15 ms 16476 KB Output is correct
8 Correct 21 ms 16732 KB Output is correct
9 Correct 24 ms 16476 KB Output is correct
10 Correct 21 ms 16732 KB Output is correct
11 Correct 21 ms 16476 KB Output is correct
12 Correct 20 ms 16472 KB Output is correct
13 Correct 21 ms 16476 KB Output is correct
14 Correct 21 ms 16476 KB Output is correct
15 Correct 21 ms 16476 KB Output is correct
16 Correct 21 ms 16472 KB Output is correct
17 Correct 16 ms 16476 KB Output is correct
18 Correct 15 ms 16472 KB Output is correct
19 Correct 14 ms 16476 KB Output is correct

Subtask #3
0 / 25.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2067 ms 16544 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 55.0

# Verdict Execution time Memory Grader output
1 Correct 56 ms 16536 KB Output is correct
2 Correct 69 ms 16588 KB Output is correct
3 Correct 56 ms 16532 KB Output is correct
4 Correct 64 ms 16720 KB Output is correct
5 Execution timed out 2057 ms 16928 KB Time limit exceeded
6 Halted 0 ms 0 KB -