UVA 699 Falling Leaves (p159, DFS of the binary tree)

Analysis: The input of this problem is the first order traversal, it is important to find this. Count the total number of leaves at each level, and you can think of the whole tree as a one-dimensional coordinate system.

#include <stdio.h>
int a[81],left,right;//Chronicle left and right boundary
void dfs (int num,int pos)
{
    int x, y;
    if (num!=-1)
    {
        if (pos<left) Left=pos;
        if (pos>right) Right=pos;
        A[pos]+=num;
        scanf ("%d", &x);//Left Dial hand tree
        DFS (x,pos-1);
        scanf ("%d", &y);//Right Sub-tree
        dfs (y,pos+1);
    }
};
int  Main ()
{
    int i,n,sum=0;
    while (scanf ("%d", &n) &&n!=-1)
    {for
        (i=0;i<81;i++) a[i]=0;
        ++sum;
        left=40;right=40;
        DFS (n,40);
        printf ("Case%d:\n", sum);
        for (i=left;i<right;i++)
        printf ("%d", A[i]);
        printf ("%d\n\n", A[right]);
    }
    return 0;
}