T9
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 674 Accepted Submission(s): 271
This led manufacturers of mobile phones to try and find an easier way to enter text on a mobile phone. The solution they developed is called T9 text input. The "9" in the name means that you can enter almost arbitrary words with just nine keys and without pressing them more than once per character. The idea of the solution is that you simply start typing the keys without repetition, and the software uses a built-in dictionary to look for the "most probable" word matching the input. For example, to enter "hello" you simply press keys 4, 3, 5, 5, and 6 once. Of course, this could also be the input for the word "gdjjm", but since this is no sensible English word, it can safely be ignored. By ruling out all other "improbable" solutions and only taking proper English words into account, this method can speed up writing of short messages considerably. Of course, if the word is not in the dictionary (like a name) then it has to be typed in manually using key repetition again.
Figure 8: The Number-keys of a mobile phone.
More precisely, with every character typed, the phone will show the most probable combination of characters it has found up to that point. Let us assume that the phone knows about the words "idea" and "hello", with "idea" occurring more often. Pressing the keys 4, 3, 5, 5, and 6, one after the other, the phone offers you "i", "id", then switches to "hel", "hell", and finally shows "hello".
Write an implementation of the T9 text input which offers the most probable character combination after every keystroke. The probability of a character combination is defined to be the sum of the probabilities of all words in the dictionary that begin with this character combination. For example, if the dictionary contains three words "hell", "hello", and "hellfire", the probability of the character combination "hell" is the sum of the probabilities of these words. If some combinations have the same probability, your program is to select the first one in alphabetic order. The user should also be able to type the beginning of words. For example, if the word "hello" is in the dictionary, the user can also enter the word "he" by pressing the keys 4 and 3 even if this word is not listed in the dictionary.
Each scenario begins with a line containing the number w of distinct words in the dictionary (0<=w<=1000). These words are given in the next w lines. (They are not guaranteed in ascending alphabetic order, although it's a dictionary.) Every line starts with the word which is a sequence of lowercase letters from the alphabet without whitespace, followed by a space and an integer p, 1<=p<=100, representing the probability of that word. No word will contain more than 100 letters.
Following the dictionary, there is a line containing a single integer m. Next follow m lines, each consisting of a sequence of at most 100 decimal digits 2-9, followed by a single 1 meaning "next word".
For every number sequence s of the scenario, print one line for every keystroke stored in s, except for the 1 at the end. In this line, print the most probable word prefix defined by the probabilities in the dictionary and the T9 selection rules explained above. Whenever none of the words in the dictionary match the given number sequence, print "MANUALLY" instead of a prefix.
Terminate the output for every number sequence with a blank line, and print an additional blank line at the end of every scenario.
這題是一道很好的字典樹,一個模擬手機輸入法的算法,要用到深搜來解決輸出哪個頻數最多的單詞。第一次寫,寫了很長時間,現在看回來,發現不過如此,鏈表不是很熟悉,要多寫多練習才行啊!
鏈接:http://acm.hdu.edu.cn/showproblem.php?pid=1298
代碼:
#include <iostream>
#include <stdio.h>
#include <cstring>
#include <string>
using namespace std;
char map[10][5];
char res[105], str[105];
int MAX;
void set() //定義map[][]
{
strcpy(map[0], "");
strcpy(map[1], "");
strcpy(map[2], "abc");
strcpy(map[3], "def");
strcpy(map[4], "ghi");
strcpy(map[5], "jkl");
strcpy(map[6], "mno");
strcpy(map[7], "pqrs");
strcpy(map[8], "tuv");
strcpy(map[9], "wxyz");
}
struct node //結點結構
{
int val; //頻率
char ch[105]; //字符
node *next[26]; //鏈表
};
node *root, memory[100005];
int cnt;
node* create()
{
node *p = &memory[cnt++];
p->val = 0;
int i;
for(i = 0; i < 26; i++)
{
p->next[i] = NULL;
}
return p;
}
void insert(char *s, int val)
{
node *p = root;
char str[105];
int i, k;
for(i = 0; s[i]; i++)
{
k = s[i] - 'a';
if(p->next[k] == NULL)
{
p->next[k] = create();
}
p = p->next[k];
p->val += val; //結點頻率相加
str[i] = s[i];
str[i+1] = 0;
strcpy(p->ch, str); //結點保存該點的字符串
}
}
void dfs(node *p, int cur, int op) //深搜字典樹(結點,當前位置,目標)
{
if(cur == op) //當前位置 == 目標位置
{
if(p->val > MAX) //找頻率最大的那個字符串
{
strcpy(res, p->ch);
MAX = p->val;
}
return;
}
int i, k, l, len;
k = str[cur+1] - '0'; //char數字->int數字
len = strlen(map[k]); //map[k]爲k鍵包含的字符
for(i = 0; i < len; i++)
{
l = map[k][i] - 'a'; //將字符->整型
if(p->next[l] == NULL) continue; //若爲空,continue
else dfs(p->next[l], cur+1, op); //否則,繼續深搜
}
}
int main()
{
int i, t, n, m, val, len, zz = 1;
char sh[105];
set();
scanf("%d", &t);
while(t--)
{
memset(memory, NULL, sizeof(memory));
cnt = 0;
root = create();
scanf("%d", &n);
for(i = 0; i < n; i++)
{
scanf("%s %d", sh, &val);
insert(sh, val); //將字符串插入字典樹中
}
printf("Scenario #%d:\n", zz++);
scanf("%d", &m);
while(m--)
{
scanf("%s", str);
len = strlen(str);
for(i = 0; str[i] != '1'; i++)
{
MAX = -1;
dfs(root, -1, i);
if(MAX != -1) printf("%s\n", res);
else printf("MANUALLY\n");
}
if(m != 0) printf("\n");
}
printf("\n\n");
}
return 0;
}