oj.uz

Submission #715137

# Submission time Handle Problem Language Result Execution time Memory
715137 2023-03-26T01:19:40 Z Pietra Pictionary (COCI18_pictionary) C++14
140 / 140
 149 ms 29252 KB 
#include<bits/stdc++.h>
using namespace std ;

const int maxl = 22 ; 
const int maxn = 2e5 + 5 ; 

int n, q, m ; 
int pai[maxn], sz[maxn], tab[maxl][maxn], nivel[maxn], mx_t[maxl][maxn] ; 
vector<pair<int,int>> grafo[maxn] ; 

struct DSU{

    int find(int a){return (pai[a] == a ? a : pai[a] = find(pai[a])) ; }

    void join(int a, int b){
        a = find(a), b = find(b) ; 
        if(a == b) return ; 
        if(sz[a] > sz[b]) swap(a, b) ; 
        sz[b] += sz[a] ; pai[a] = b ; 
    }

} dsu ; 

void dfs(int v, int p){

    tab[0][v] = p ; 

    for(auto a : grafo[v]){
        if(a.first == p || nivel[a.first] != -1) continue ;
        mx_t[0][a.first] = a.second ; 
        nivel[a.first] = nivel[v] + 1 ; 
        dfs(a.first, v) ; 
    }

}

int lca(int a, int b){

    if(nivel[a] > nivel[b]) swap(a, b) ; 

    int ans = 0 ; 

    for(int i = maxl - 1 ; i >= 0 ; i--){
        if(tab[i][b] != -1 && nivel[tab[i][b]] >= nivel[a]){
            ans = max(ans, mx_t[i][b]) ; 
            b = tab[i][b] ; 
        }
    }

    if(a == b) return ans ; 

    for(int i = maxl - 1 ; i >= 0 ; i--){
        if(tab[i][a] != -1 && tab[i][b] != -1 && tab[i][a] != tab[i][b]){
            ans = max({ans, mx_t[i][a], mx_t[i][b]}) ; 
            a = tab[i][a], b = tab[i][b] ;
        }
    }

    return max({ans, mx_t[0][a], mx_t[0][b]}) ;

}

int main(){

    ios_base::sync_with_stdio(false) ; cin.tie(NULL) ; 

    cin >> n >> m >> q ; 

    for(int i = 1 ; i <= n ; i++) nivel[i] = -1, pai[i] = i, sz[i] = 1 ; 

    for(int i = m ; i > 0 ; i--){
        for(int j = i + i ; j <= n ; j += i){
            if(dsu.find(i) == dsu.find(j)) continue ; 
            dsu.join(i, j) ; 
            grafo[i].push_back({j, m-i+1}) ; grafo[j].push_back({i, m-i+1}) ;
        }
    }

    for(int i = 1 ; i < maxl ; i++){
        for(int j = 1 ; j <= n ; j++) tab[i][j] = -1 ; 
    }

    nivel[1] = 0 ; 
    dfs(1, 0) ; 

    for(int i = 1 ; i < maxl ; i++){
        for(int j = 1 ; j <= n ; j++){
            if(tab[i-1][j] == -1) continue ; 
            tab[i][j] = tab[i-1][tab[i-1][j]] ; 
            mx_t[i][j] = max(mx_t[i-1][j], mx_t[i-1][tab[i-1][j]]) ;
        }
    }

    for(int i = 1 ; i <= q ; i++){
        int a, b ; cin >> a >> b ; 
        cout << lca(a, b) << "\n" ;
    }

}

Subtask #1
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5332 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 12 ms 5716 KB Output is correct

Subtask #3
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 6288 KB Output is correct
2 Correct 43 ms 6284 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 54 ms 6756 KB Output is correct
2 Correct 48 ms 6568 KB Output is correct

Subtask #5
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 53 ms 11148 KB Output is correct
2 Correct 46 ms 10912 KB Output is correct

Subtask #6
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 36 ms 13004 KB Output is correct
2 Correct 41 ms 14080 KB Output is correct

Subtask #7
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 71 ms 16500 KB Output is correct
2 Correct 52 ms 16960 KB Output is correct

Subtask #8
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 103 ms 20496 KB Output is correct
2 Correct 85 ms 22024 KB Output is correct

Subtask #9
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 138 ms 23908 KB Output is correct
2 Correct 112 ms 26688 KB Output is correct

Subtask #10
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 149 ms 29044 KB Output is correct
2 Correct 134 ms 29252 KB Output is correct