题解

#include <iostream>
#include <vector>
#include <unordered_map>
#include <algorithm>
 
using namespace std;
 
void previousPermutation(vector<int>& perm) {
    int n = perm.size(); 
    int i = n - 1;
    while (i > 0 && perm[i - 1] <= perm[i]) {
        i--;
    }
    if (i <= 0) {
        reverse(perm.begin(),  perm.end()); 
        return;
    }
    int j = n - 1;
    while (perm[j] >= perm[i - 1]) {
        j--;
    }
    swap(perm[i - 1], perm[j]);
    reverse(perm.begin()  + i, perm.end()); 
}
 
int main() {
    int n;
    cin >> n;
    vector<int> initial(n);
    for (int i = 0; i < n; ++i) {
        cin >> initial[i];
    }
    vector<int> current(n);
    for (int i = 0; i < n; ++i) {
        cin >> current[i];
    }
    unordered_map<int, int> position;
    for (int i = 0; i < n; ++i) {
        position[initial[i]] = i;
    }
    vector<int> indices(n);
    for (int i = 0; i < n; ++i) {
        indices[i] = position[current[i]];
    }
    previousPermutation(indices);
    vector<int> result(n);
    for (int i = 0; i < n; ++i) {
        result[i] = initial[indices[i]];
    }
    for (int i = 0; i < n; ++i) {
        if (i > 0) cout << " ";
        cout << result[i];
    }
    cout << endl;
    
    return 0;
}