POJ 2001 Shortest Prefixes

Shortest Prefixes

Time Limit: 1000MS Memory Limit: 30000KTotal Submissions: 19683 Accepted: 8538

Description

A prefix of a string is a substring starting at the beginning of the given string. The prefixes of "carbon" are: "c", "ca", "car", "carb", "carbo", and "carbon". Note that the empty string is not considered a prefix in this problem, but every non-empty string is considered to be a prefix of itself. In everyday language, we tend to abbreviate words by prefixes. For example, "carbohydrate" is commonly abbreviated by "carb". In this problem, given a set of words, you will find for each word the shortest prefix that uniquely identifies the word it represents. 

In the sample input below, "carbohydrate" can be abbreviated to "carboh", but it cannot be abbreviated to "carbo" (or anything shorter) because there are other words in the list that begin with "carbo". 

An exact match will override a prefix match. For example, the prefix "car" matches the given word "car" exactly. Therefore, it is understood without ambiguity that "car" is an abbreviation for "car" , not for "carriage" or any of the other words in the list that begins with "car". 

Input

The input contains at least two, but no more than 1000 lines. Each line contains one word consisting of 1 to 20 lower case letters.

Output

The output contains the same number of lines as the input. Each line of the output contains the word from the corresponding line of the input, followed by one blank space, and the shortest prefix that uniquely (without ambiguity) identifies this word.

Sample Input

carbohydratecartcarburetorcaramelcariboucarboniccartilagecarboncarriagecartoncarcarbonate

Sample Output

carbohydrate carbohcart cartcarburetor carbucaramel caracaribou caricarbonic carbonicartilage carticarbon carboncarriage carrcarton cartocar carcarbonate carbona

Source

Rocky Mountain 2004

题目大意：找出能标记该字符串的最短前缀，如果不行的话，就输出该字符串

字典树模板题

#include<iostream>#include<cstdio>#include<cstring>using namespace std;char str[1010][50];struct Node{int cnt;Node *next[26];}*root;void init(){root=new Node;for(int i=0;i<26;i++)root->next[i]=NULL;}void insert(char *str){Node *ptr=root;int len=strlen(str);for(int i=0;i<len;i++){int tmp=str[i]-'a';if(ptr->next[tmp]==NULL){ptr->next[tmp]=new Node;ptr=ptr->next[tmp];ptr->cnt=1;for(int i=0;i<26;i++){ptr->next[i]=NULL;}}else{ptr=ptr->next[tmp];ptr->cnt++;}}return;}void search(char *str){int len=strlen(str);Node* ptr=root;for(int i=0;i<len;i++){putchar(str[i]);int tmp=str[i]-'a';ptr=ptr->next[tmp];if(ptr->cnt==1) break;}putchar('\n');return;}int main(){int cnt=0;init();while(~scanf("%s",str[cnt])){insert(str[cnt++]);}for(int i=0;i<cnt;i++){cout<<str[i]<<' ';search(str[i]);}}