1. 題目
在老式手機上,使用者通過數字鍵盤輸入,手機将提供與這些數字相比對的單詞清單。
每個數字映射到0至4個字母。給定一個數字序列,實作一個算法來傳回比對單詞的清單。
你會得到一張含有有效單詞的清單。映射如下圖所示:
示例 1:
輸入: num = "8733", words = ["tree", "used"]
輸出: ["tree", "used"]
示例 2:
輸入: num = "2", words = ["a", "b", "c", "d"]
輸出: ["a", "b", "c"]
提示:
num.length <= 1000
words.length <= 500
words[i].length == num.length
num中不會出現 0, 1 這兩個數字
複制
來源:力扣(LeetCode)
連結:https://leetcode-cn.com/problems/t9-lcci
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2. 解題
類似題目:LeetCode 17. 電話号碼的字母組合(回溯)
class Solution {
public:
vector<string> getValidT9Words(string num, vector<string>& words) {
string key[10] = {"","","abc","def","ghi","jkl","mno","pqrs","tuv","wxyz"};
vector<string> ans;
int i;
bool ok;
for(auto& w : words)
{
ok = true;
for(i = 0; i < w.size(); ++i)
{
if(key[num[i]-'0'].find(w[i]) == string::npos)
{
ok = false;
break;
}
}
if(ok)
ans.push_back(w);
}
return ans;
}
};
複制
36 ms 12.2 MB
- 或者比較數字是否相等
class Solution {
public:
vector<string> getValidT9Words(string num, vector<string>& words) {
char ch[26] = {'2', '2', '2', '3', '3', '3', '4', '4', '4',
'5', '5', '5', '6', '6', '6', '7', '7', '7', '7',
'8', '8', '8', '9', '9', '9', '9'};
vector<string> ans;
int i;
bool ok;
for(auto& w : words)
{
ok = true;
for(i = 0; i < w.size(); ++i)
{
if(num[i] != ch[w[i]-'a'])
{
ok = false;
break;
}
}
if(ok)
ans.push_back(w);
}
return ans;
}
};
複制
28 ms 12 MB