Blogs Hub

by Sumit Chourasia | May 30, 2020 | Category :coding | Tags : डेटा-संरचनाstringalgorithmआसानleetcode

Check If a Word Occurs As a Prefix of Any Word in a Sentence - मिनी टीवी

Given a sentence that consists of some words separated by a single space, and a searchWord.

You have to check if searchWord is a prefix of any word in sentence.

Return the index of the word in sentence where searchWord is a prefix of this word (1-indexed).

If searchWord is a prefix of more than one word, return the index of the first word (minimum index). If there is no such word return -1.

A prefix of a string S is any leading contiguous substring of S.

Example 1:

``````Input: sentence = "i love eating burger", searchWord = "burg"

Output: 4

Explanation: "burg" is prefix of "burger" which is the 4th word in the sentence.``````

Example 2:

``````Input: sentence = "this problem is an easy problem", searchWord = "pro"

Output: 2

Explanation: "pro" is prefix of "problem" which is the 2nd and the 6th word in the sentence, but we return 2 as it's the minimal index.``````

Example 3:

``````Input: sentence = "i am tired", searchWord = "you"

Output: -1

Explanation: "you" is not a prefix of any word in the sentence.``````

Example 4:

``````Input: sentence = "i use triple pillow", searchWord = "pill"

Output: 4``````

Example 5:

``````Input: sentence = "hello from the other side", searchWord = "they"

Output: -1``````

Constraints:

``````1 <= sentence.length <= 100

1 <= searchWord.length <= 10

sentence consists of lowercase English letters and spaces.

searchWord consists of lowercase English letters.``````

Solution:

``````using System;
using System.Collections.Generic;
using System.Text;

{
public class IsPrefixOfWordSoln
{
public int IsPrefixOfWord(string sentence, string searchWord)
{
var word = 1;
bool isBeginingOfWord = true;
for(int i = 0; i < sentence.Length; i++)
{
if (isBeginingOfWord)
{
isBeginingOfWord = false;
if (IsWordAPrefix(sentence, searchWord, i))
{
return word;
}
word++;
}
if(sentence[i] == ' ')
{
isBeginingOfWord = true;
}
}
return -1;
}

private bool IsWordAPrefix(string sentence, string searchWord, int i)
{
for(int j = 0; j < searchWord.Length; j++)
{
if(sentence[i+j] != searchWord[j])
{
return false;
}
}

return true;
}
}
}
``````

Time Complexity: O(n)

Space Complexity: O(1)

Unit Tests:

``````using LeetCode.AskGif.Easy.String;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System;
using System.Collections.Generic;
using System.Text;

namespace CodingUnitTest.Easy.String
{
[TestClass]
public class IsPrefixOfWordSolnTests
{
[TestMethod]
public void IsPrefixOfWordSoln_First()
{
var sentence = "i love eating burger";
var searchWord = "burg";
var output = 4;
var res = new IsPrefixOfWordSoln().IsPrefixOfWord(sentence, searchWord);

Assert.AreEqual(res, output);
}

[TestMethod]
public void IsPrefixOfWordSoln_Second()
{
var sentence = "this problem is an easy problem";
var searchWord = "pro";
var output = 2;
var res = new IsPrefixOfWordSoln().IsPrefixOfWord(sentence, searchWord);

Assert.AreEqual(res, output);
}

[TestMethod]
public void IsPrefixOfWordSoln_Fourth()
{
var sentence = "i use triple pillow";
var searchWord = "pill";
var output = 4;
var res = new IsPrefixOfWordSoln().IsPrefixOfWord(sentence, searchWord);

Assert.AreEqual(res, output);
}

[TestMethod]
public void IsPrefixOfWordSoln_Third()
{
var sentence = "i am tired";
var searchWord = "you";
var output = -1;
var res = new IsPrefixOfWordSoln().IsPrefixOfWord(sentence, searchWord);

Assert.AreEqual(res, output);
}

[TestMethod]
public void IsPrefixOfWordSoln_Fifth()
{
var sentence = "hello from the other side";
var searchWord = "they";
var output = -1;
var res = new IsPrefixOfWordSoln().IsPrefixOfWord(sentence, searchWord);

Assert.AreEqual(res, output);
}
}
}
``````

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia