题解时间超速———C语言输入输出

#include<cstdio>
using namespace std;
struct tree{
int root;
int left;
int right;
}a[101];
int n;
void dfs_first(int x)
{
    printf("%d",x);
    printf("%c",' ');
    if(a[x].left!=0)dfs_first(a[x].left);
    if(a[x].right!=0)dfs_first(a[x].right);
}
void dfs_second(int x)
{
    if(a[x].left!=0)dfs_second(a[x].left);
    printf("%d",x);
    printf("%c",' ');
    if(a[x].right!=0)dfs_second(a[x].right);
}
void dfs_third(int x)
{
    if(a[x].left!=0)dfs_third(a[x].left);
    if(a[x].right!=0)dfs_third(a[x].right);
    printf("%d",x);
    printf("%c",' ');
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
        {
            scanf("%d%d%d",&a[i].root,&a[i].left,&a[i].right);
        }
    dfs_first(1);
    printf("%c",'\n');
    dfs_second(1);
    printf("%c",'\n');
    dfs_third(1);
    return 0;
}