分治原理
动画实验台

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

void quickSort(vector<int>& a, int left, int right) {
    if (left >= right) return;

    int pivot = a[left + (right - left) / 2];
    int i = left, j = right;

    while (i <= j) {
        while (a[i] < pivot) ++i;
        while (a[j] > pivot) --j;

        if (i <= j) {
            swap(a[i], a[j]);
            ++i;
            --j;
        }
    }

    if (left < j) quickSort(a, left, j);
    if (i < right) quickSort(a, i, right);
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;
    vector<int> a(n);
    for (int& x : a) cin >> x;

    quickSort(a, 0, n - 1);

    for (int x : a) cout << x << ' ';
    cout << '\n';
    return 0;
}

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

void mergeSort(vector<int>& a, vector<int>& temp,
               int left, int right) {
    if (left >= right) return;

    int mid = left + (right - left) / 2;
    mergeSort(a, temp, left, mid);
    mergeSort(a, temp, mid + 1, right);

    int i = left, j = mid + 1, k = left;
    while (i <= mid && j <= right) {
        if (a[i] <= a[j]) temp[k++] = a[i++];
        else temp[k++] = a[j++];
    }

    while (i <= mid) temp[k++] = a[i++];
    while (j <= right) temp[k++] = a[j++];

    for (int p = left; p <= right; ++p) {
        a[p] = temp[p];
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;
    vector<int> a(n), temp(n);
    for (int& x : a) cin >> x;

    mergeSort(a, temp, 0, n - 1);

    for (int x : a) cout << x << ' ';
    cout << '\n';
    return 0;
}