POJ 1056 解题报告 Trie 树

#include <cstdio>
#include <cstring>

#define maxn 10
#define wlen 10 //单词长度
#define character '0'
#define size 2

typedef struct node {
int cnt; //记录访问量
int child_num; //记录孩子个数
int childs[size];
void init()
{
cnt = 1;
child_num = 0;
memset(childs, 0, sizeof(childs));
}
} Node;

Node ns[maxn * wlen];
int root;
int node_cnt = 0; //trie 树的结点数
char input[12];

int insert(char *s)
{
int r = 0, index, child;
for (int i = 0; s[i] != '\0'; ++i) {
index = s[i] - character;
child = ns[r].childs[index];
if (child != 0) {
ns[child].cnt++;
r = child;
}
else {
if (i > 0 && ns[r].cnt > 1 && ns[r].child_num == 0) return 0;
ns[++node_cnt].init();
ns[r].childs[index] = node_cnt;
ns[r].child_num++;
r = node_cnt;
}
}
if (ns[r].child_num != 0) return 0;
else return 1;
}

int query(char *s)
{
int r = 0, index, child;
for (int i = 0; s[i] != '\0'; ++i) {
index = s[i] - character;
child = ns[r].childs[index];
if (child == 0) {
return 0;
}
else {
r = child;
}
}
return ns[r].cnt;
}

int main()
{
//freopen("testdata/1056.txt", "r", stdin);
int flag = 1, c = 1;
while (scanf("%s", input) != EOF) {
if (input[0] == '9') {
node_cnt = 0;
ns[node_cnt].init();
if (flag) printf("Set %d is immediately decodable\n", c++);
else printf("Set %d is not immediately decodable\n", c++);
flag = 1;
continue;
}
if (flag) {
if (insert(input) == 0) flag = 0;
}

}
return 0;
}