[C++知识库]hdu5 1006 Cute Tree ...

题解：就是根据给的代码片改成C++语言

• 第一发超时：把给的代码片中没用的 for 循环去掉
• 第二发runtime error：将数组大小开大一点过了

accode:

#include <stdio.h>
#include <math.h>
using namespace std;
typedef long long ll;
const int maxn = 2e6 + 10;
int a[maxn], key[maxn];
int son[maxn][4];
int tot;

ll BT(int id, int L, int R)
{
    int mid;
    tot++;
    id = tot;
    int B, C;
    if(L == R)
    {
        key[id] = a[L];
        return tot;
    }
    else if(R - L == 1)
    {
        mid = (L + R) / 2;
        BT(son[id][0], L, L);
        BT(son[id][1], R, R);
    }
    else
    {
        B = L + ceil(1.0 * (R - L) / 3) - 1;//上取整 
        C = (B + R) / 2;
        BT(son[id][0], L, B);
        BT(son[id][1], B+1, C);
        BT(son[id][2], C+1, R);
    }
}

int main()
{
    int T, n;
    scanf("%d", &T);
    while(T--)
    {
        tot = 0;
        scanf("%d", &n);
        for(int i = 1; i <= n; i++)
            scanf("%d", &a[i]);
        int root;
        BT(root, 1, n);
        printf("%d\n", tot);
    }
        
    return 0;
}