CDOJ_1063 秋实大哥与妹纸（堆结构）

把所有的同类数据按照大小的顺序排列。如果数据的个数是奇数，则中间那个数据就是这群数据的中位数；如果数据的个数是偶数，则中间那2个数据的算术平均值就是这群数据的中位数。

Input

Output

Sample input and output

3
1
2
3

2.0

Hint

Source

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define maxn 125005
unsigned int num[maxn];
void heap_output(unsigned int *num, int n)
{
int i;
for (i = 0; i < n; i++)
printf("%u ", num[i]);
printf("\n");
}
void heap_make(unsigned int *num, int s, int n)
{
int j; unsigned int t;
while (2 * s + 1 < n)
{
j = 2 * s + 1;
if (j + 1 < n)
{
if (num[j] < num[j + 1])
j++;
}
if (num[s] < num[j])
{
t = num[s];
num[s] = num[j];
num[j] = t;
s = j;
}
else break;
}
}
int main()
{
unsigned int temp;
int n, mid;
double ans;
scanf("%d", &n);
memset(num, 0, sizeof(unsigned int)*maxn);
mid = n / 2 + 1;
int i;
for (i = 0; i < mid; i++)
scanf("%u", &num[i]);
for (i = mid / 2 - 1; i >= 0; i--)
heap_make(num, i, mid);

for (i = mid; i < n; i++)
{
scanf("%u", &temp);
if (temp < num[0])
{
num[0] = temp;
heap_make(num, 0, mid);
}
}

if (n % 2)
{
ans = num[0];
}
else
{
double t1, t2;
t1 = num[0];
t2 = (num[1] > num[2]) ? num[1] : num[2];
ans = (t1 + t2) / 2.0;
}
printf("%.1f", ans);

return 0;
}