AcWing 787. 归并排序
原题链接
简单
作者:
tq
,
2024-04-13 11:33:21
,
所有人可见
,
阅读 5
//第二遍错
//归并排序:关键是分成左右两半数组,再比较开头的数,小的则存到暂存数组中,但注意暂存要赋回来给a
#include <iostream>
using namespace std;
const int N = 100010;
int a[N], r[N], tmp[N];
void merge_sort(int a[], int l, int r){
if(l >= r) return;
int x = l + r >> 1;
merge_sort(a, l, x);
merge_sort(a, x + 1, r);
int i = l, j = x + 1, k = 0;
while(i <= x && j <= r){
if(a[i] < a[j]) {
tmp[k ++] = a[i]; //你递归过程中,需要用新数组来存储新排序,但是新数组怎么递归呢
i ++;
}
else {
tmp[k ++] = a[j];
j ++;
}
}
while(i <= x) { //左半边没排完
tmp[k ++] = a[i];
i ++;
}
while(j <= r){
tmp[k ++] = a[j];
j ++;
}
for(int i = l, j = 0; i <= r; i ++, j ++) //赋回给a
a[i] = tmp[j];
return;
}
int main(){
int n;
scanf("%d", &n);
for(int i = 0; i < n; i ++)
scanf("%d", &a[i]);
merge_sort(a, 0, n - 1);
for(int i = 0; i < n; i ++)
printf("%d ", a[i]);
}