POJ 1056 IMMEDIATE DECODABILITY(字典树 水题)
来源:互联网 发布:网络教学有什么特点 编辑:程序博客网 时间:2024/06/06 15:02
IMMEDIATE DECODABILITY
Time Limit: 1000MS Memory Limit: 10000KTotal Submissions: 13014 Accepted: 6235
Description
An encoding of a set of symbols is said to be immediately decodable if no code for one symbol is the prefix of a code for another symbol. We will assume for this problem that all codes are in binary, that no two codes within a set of codes are the same, that each code has at least one bit and no more than ten bits, and that each set has at least two codes and no more than eight.
Examples: Assume an alphabet that has symbols {A, B, C, D}
The following code is immediately decodable:
A:01 B:10 C:0010 D:0000
but this one is not:
A:01 B:10 C:010 D:0000 (Note that A is a prefix of C)
Examples: Assume an alphabet that has symbols {A, B, C, D}
The following code is immediately decodable:
A:01 B:10 C:0010 D:0000
but this one is not:
A:01 B:10 C:010 D:0000 (Note that A is a prefix of C)
Input
Write a program that accepts as input a series of groups of records from standard input. Each record in a group contains a collection of zeroes and ones representing a binary code for a different symbol. Each group is followed by a single separator record containing a single 9; the separator records are not part of the group. Each group is independent of other groups; the codes in one group are not related to codes in any other group (that is, each group is to be processed independently).
Output
For each group, your program should determine whether the codes in that group are immediately decodable, and should print a single output line giving the group number and stating whether the group is, or is not, immediately decodable.
Sample Input
0110001000009011001000009
Sample Output
Set 1 is immediately decodableSet 2 is not immediately decodable
【题意】要求所给字符串是否有的是其他字符串的前缀。
【解题方法】可以想到字典树,字典树的一个分支记录一个字符串,叶子节点做相应的标记。如果在字典树上插入新字符串的时候经过先前的叶子节点标记,则说明以该节点为叶子节点的路径上的字符串是当前插入字符串的前缀;如果在字典树上插入新字符串的长度小于当前所在的分支,则说明当前插入字符串是经过当前路径的所有分支所标示的字符串的前缀。
【AC 代码】
#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>using namespace std;const int maxn = 100010;char s[20];bool ff;struct Trie{int root,sz,nxt[maxn][2],flag[maxn];int newnode(){ flag[sz]=0; nxt[sz][0]=nxt[sz][1]=-1; return sz++;}void init(){ sz=0; root=newnode();}void insert(char *s){ int u=root,n=strlen(s); for(int i=0; i<n; i++){ int &v=nxt[u][s[i]-'0']; if(v!=-1) { if(flag[v]||i==n-1) { ff=false; return ; } } else{ v=newnode(); } u=v; } flag[u]=1;}}trie;int main(){int cas=1;while(scanf("%s",s)!=EOF){ff=true;trie.init();trie.insert(s);while(scanf("%s",s)){if(strcmp(s,"9")==0) break;if(ff) trie.insert(s);}if(!ff) printf("Set %d is not immediately decodable\n",cas++);else printf("Set %d is immediately decodable\n",cas++);}return 0;}
0 0
- POJ 1056 IMMEDIATE DECODABILITY(字典树 水题)
- POJ 1056 IMMEDIATE DECODABILITY (字典树)
- POJ 1056 IMMEDIATE DECODABILITY 字典树
- poj 1056 IMMEDIATE DECODABILITY 字典树
- POJ 1056 IMMEDIATE DECODABILITY(字典树)
- poj 1056 IMMEDIATE DECODABILITY 字典树
- POJ 1056 IMMEDIATE DECODABILITY 字典树
- poj 1056 IMMEDIATE DECODABILITY(字典树)
- POJ 题目1056 IMMEDIATE DECODABILITY(字典树)
- Immediate Decodability 字典树
- IMMEDIATE DECODABILITY(字典树)
- Immediate Decodability-字典树
- poj 1056 : immediate decodability
- POJ 1056 IMMEDIATE DECODABILITY
- POJ 1056 IMMEDIATE DECODABILITY
- <poj 1056>IMMEDIATE DECODABILITY
- poj 1056 IMMEDIATE DECODABILITY
- poj 1056 IMMEDIATE DECODABILITY
- HPU图论专项(graph)【拓扑--二分图--最小生成树---树的直径---并查集--奇偶树---最小环---强联通】
- C语言内存分配
- Java中ArrayList和LinkedList区别
- SVN数据迁移
- 使用Java开发高性能网站需要关注的那些事儿
- POJ 1056 IMMEDIATE DECODABILITY(字典树 水题)
- java泛型反射总结
- 技术博客网站推荐
- mysql5.7的archive版本在win10下安装小记
- 进程与线程的区别
- Android普通的5种对话框
- C++中的智能指针——auto_ptr, unique_ptr, shared_ptr和weak_ptr
- Python版的Word2Vec -- gensim 学习手札 中文词语相似性度量 V1.1
- 李开复给大学生的第6封信:选择的智慧