P1177 【模板】快速排序

可以用快排的板测

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
#include<bits/stdc++.h>
using namespace std;
const int MAXn = 100000;

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

int n;
int a[MAXn + 10];
int tmp[MAXn + 10];
void merge(int l, int r) {
    if (r - l <= 1) {
        return;
    }
    int mid = l + (r - l >> 1);
    merge(l, mid);
    merge(mid, r);
    int p = l, q = mid, s = l;
    while (s < r) {
        if (p >= mid || (q < r && a[p] > a[q])) {
            tmp[s++] = a[q++];
        } else {
            tmp[s++] = a[p++];          
        }
    }
    for (int i = l; i < r; i++) {
        a[i] = tmp[i];
    }
}

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