P1177 【模板】快速排序

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#include<bits/stdc++.h>
using namespace std;
const int MAXn = 100000;

inline int read() {
    char c;
    while (c = getchar(), c < '0' || c > '9');
    int x(c - '0');
    while (c = getchar(), c >= '0' && c <= '9') {
        x = x * 10 + c - '0';
    }
    return x;
}

int n;
int a[MAXn + 10];
void _QuickSort_(int* a, int l, int r) {
    int i = l, j = r, f = a[(l + r) / 2];
    do {
        while (a[i] < f) {
            i++;
        }
        while (a[j] > f) {
            j--;
        }
        if (i <= j) {
            int tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
            i++;
            j--;
        }
    } while (i <= j);
    if (l < j) {
        _QuickSort_(a, l, j);
    }
    if (i < r) {
        _QuickSort_(a, i, r);
    }
}

void QuickSort(int* a, int l, int r) {
    _QuickSort_(a, l, r - 1);
}

int main() {
    n = read();
    for (int i = 0; i < n; i++) {
        a[i] = read();
    }
    QuickSort(a, 0, n);
    for (int i = 0; i < n; i++) {
        printf("%d ", a[i]);
    }
}