数据结构实验之查找三：树的种类统计（SDUT 3375）

C++：

#include <bits/stdc++.h>

using namespace std;

int n;

struct node
{
    char data[55];
    int num;
    struct node *lc, *rc;
};

void creat(struct node *&root,char s[])
{
    if(root == NULL)
    {
        root = (struct node *)malloc(sizeof(struct node ));
        strcpy(root->data,s);
        root -> lc = root -> rc = NULL;
        root -> num = 1;
    }
    else {
        int f = strcmp(root->data,s);
        if(f > 0)
        {
            creat(root -> lc,s);
        }
        else if(f < 0)
        {
            creat(root -> rc, s);
        }
        else root -> num ++;
    }
}

void fin(struct node *root)
{
    if(root)
    {
        fin(root->lc);
        printf("%s %.2lf%c
",root -> data,root -> num *100.0 / n,'%');
        fin(root -> rc);
    }
}
char s[55];
int main()
{

    struct node *root;
    root = NULL;
    scanf("%d",&n);
    getchar();
    for(int i = 0; i < n; i ++)
    {
        gets(s);
        for(int j = 0; j < strlen(s); j ++)
        {
            if(s[j] >= 'A' && s[j] <= 'Z')
            {
                s[j] = s[j] -'A' + 'a';
            }
        }
        creat(root,s);
    }
    fin(root);
    return 0;
}