Shortest Prefixes
Time Limit: 1000MSMemory Limit: 30000K
Total Submissions: 14535Accepted: 6277
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
题意：求给出的每个单词的“标志前缀”，即此前缀只能在此单词中有，而其他单词不拥有，，所以叫做标志前缀。分析：很明显的运用字典树求解。题目链接：?id=2001代码清单：#include<cstdio>#include<cstring>#include<iostream>#include<algorithm>const int MAX = 27 ;const int MAXS = 21 ;const int MAXN = 1005 ;struct trie{int point;trie *next[MAX];};trie *root=new trie;char str[MAXN][MAXS];int number=0;void createTrie(char *s){trie *p=root,*q;int len=strlen(s),pos;for(int i=0;i<len;i++){pos=s[i]-'a';if(p->next[pos]==NULL){q=new trie;q->point=1;for(int j=0;j<MAX;j++)q->next[j]=NULL;p->next[pos]=q;p=p->next[pos];}else{p->next[pos]->point++;p=p->next[pos];}}}void findTrie(char *s){trie *p=root;int len=strlen(s),pos;for(int i=0;i<len;i++){pos=s[i]-'a';printf("%c",s[i]);if(p->next[pos]->point==1)break;p=p->next[pos];}printf("\n");}void delTrie(trie *Root){for(int i=0;i<MAX;i++){if(Root->next[i]!=NULL)delTrie(Root->next[i]);}free(Root);}int main(){//freopen("liuchu.txt","r",stdin);for(int i=0;i<MAX;i++)root->next[i]=NULL;while(scanf("%s",str[number])!=EOF){createTrie(str[number]);number++;}for(int i=0;i<number;i++){printf("%s ",str[i]);findTrie(str[i]);}free(root);return 0;}
人生才会更有意义。如果没有梦想，那就托做庸人。
