Rumah >pembangunan bahagian belakang >C++ >Program C++ untuk mencari nilai maksimum i
Katakan kita mempunyai jujukan integer 'seq' dan tatasusunan pasangan integer 'pasangan' saiz m, yang mengandungi integer 0 hingga n - 1. Sekarang, kami melakukan operasi berikut pada seq sebanyak mungkin supaya seq[i] = i (0 ≤ i
Kita perlu memilih integer j di mana 0
Kami mesti mencari nilai maksimum i supaya seq[i] = i selepas melakukan operasi beberapa kali.
Jadi jika input ialah n = 4, m = 2, seq = {0, 3, 2, 1}, pasangan = {{0, 1}, {2, 3}}, maka outputnya ialah 2.
Nilai maksimum yang mungkin adalah 2.
Untuk menyelesaikan masalah ini, kami akan mengikuti langkah berikut:
N := 100 Define an array tp of size: N. Define arrays vtmp, vis of size N. Define a function dfs(), this will take j, k, tp[j] := k insert j at the end of vtmp[k] for each value b in vis[j], do: if tp[b] is not equal to 0, then: Ignore following part, skip to the next iteration dfs(b, k) res := 0 for initialize i := 0, when i < n, update (increase i by 1), do: if seq[i] is same as i, then: (increase res by 1) for initialize i := 0, when i < m, update (increase i by 1), do: a := first value of pairs[i] b := second value of pairs[i] insert b at the end of vis[a] insert a at the end of vis[b] idx := 1 for initialize i := 0, when i < n, update (increase i by 1), do: if tp[i] is same as 0, then: dfs(i, idx) for each element j in vtmp[idx], do: if tp[seq[j]] is same as idx and seq[j] is not equal to j, then: (increase res by 1) (increase idx by 1) print(res)
Mari kita lihat pelaksanaan di bawah untuk pemahaman yang lebih baik −
#include <bits/stdc++.h> using namespace std; const int INF = 1e9; #define N 100 int tp[N]; vector<int> vtmp[N], vis[N]; void dfs(int j, int k){ tp[j] = k; vtmp[k].push_back(j); for(auto b : vis[j]) { if(tp[b] != 0) continue; dfs(b, k); } } void solve(int n, int m, int seq[], vector<pair<int, int>> pairs) { int res = 0; for(int i = 0; i < n; i++){ if(seq[i] == i) res++; } for(int i = 0; i < m; i++){ int a = pairs[i].first; int b = pairs[i].second; vis[a].push_back(b); vis[b].push_back(a); } int idx = 1; for(int i = 0; i < n; i++) { if(tp[i] == 0) { dfs(i, idx); for(auto j: vtmp[idx]){ if(tp[seq[j]] == idx && seq[j] != j) res++; } idx++; } } cout<< res; } int main() { int n = 4, m = 2, seq[] = {0, 3, 2, 1}; vector<pair<int,int>> pairs = {{0, 1}, {2, 3}}; solve(n, m, seq, pairs); return 0; }
4, 2, {0, 3, 2, 1}, {{0, 1}, {2, 3}}
2
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