Capitalize the Title

Capitalize the Title - Problem

String Easy

You are given a string title consisting of one or more words separated by a single space, where each word consists of English letters. Capitalize the string by changing the capitalization of each word such that:

If the length of the word is 1 or 2 letters, change all letters to lowercase.
Otherwise, change the first letter to uppercase and the remaining letters to lowercase.

Return the capitalized title.

Input & Output

Example 1 — Mixed Case Input

$ Input: title = "capiTalIze tHe titLe"

› Output: "Capitalize The Title"

💡 Note: "capiTalIze" has 10 letters (>2) → "Capitalize", "tHe" has 3 letters (>2) → "The", "titLe" has 5 letters (>2) → "Title"

Example 2 — Short Words

$ Input: title = "First leTTeR of EACH Word"

› Output: "First Letter of Each Word"

💡 Note: "First" → "First" (5 letters), "leTTeR" → "Letter" (6 letters), "of" → "of" (2 letters, stays lowercase), "EACH" → "Each" (4 letters), "Word" → "Word" (4 letters)

Example 3 — Very Short Words

$ Input: title = "i lOve Y"

› Output: "i love y"

💡 Note: All words have ≤2 letters: "i" (1 letter) → "i", "lOve" (4 letters) → "Love", "Y" (1 letter) → "y"

Constraints

1 ≤ title.length ≤ 100
title consists of words separated by a single space without leading or trailing spaces
Each word consists of uppercase and lowercase English letters only

Visualization

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Asked in

🍎 Apple 15 M Microsoft 12

The key insight is that word length determines capitalization: words with ≤2 letters become lowercase, longer words become title case. Best approach is to split by spaces and process each word individually. Time: O(n), Space: O(n)

Common Approaches

✓ Character-by-Character Processing

⏱️ Time: O(n) Space: O(1)

Iterate through the string character by character, identifying word boundaries by spaces. For each word, determine its length and apply the appropriate capitalization rule by modifying each character.

Split and Process Words

⏱️ Time: O(n) Space: O(n)

Split the input string by spaces to get individual words. For each word, check its length and apply the appropriate capitalization rule using built-in string methods. Finally, join all processed words with spaces.

Character-by-Character Processing — Algorithm Steps

Step 1: Iterate through each character in the string
Step 2: Track current word and its length using word boundaries
Step 3: Apply capitalization rules based on word length
Step 4: Build result string character by character

Visualization

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Step-by-Step Walkthrough

Scan Characters

Move through string tracking word boundaries

Check Length

Determine word length when space is found

Apply Rules

Capitalize based on length: ≤2 lowercase, >2 title case

Code -

solution.c — C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

char* solution(char* title) {
    if (!title || strlen(title) == 0) {
        char* result = malloc(1);
        result[0] = '\0';
        return result;
    }
    
    int len = strlen(title);
    char* result = malloc(len + 1);
    int resultIdx = 0;
    int i = 0;
    
    while (i < len) {
        if (title[i] == ' ') {
            result[resultIdx++] = ' ';
            i++;
            continue;
        }
        
        // Start of a word - find its end
        int wordStart = i;
        while (i < len && title[i] != ' ') {
            i++;
        }
        
        int wordLength = i - wordStart;
        
        // Apply capitalization rules
        for (int j = wordStart; j < i; j++) {
            if (wordLength <= 2) {
                result[resultIdx++] = tolower(title[j]);
            } else {
                if (j == wordStart) {
                    result[resultIdx++] = toupper(title[j]);
                } else {
                    result[resultIdx++] = tolower(title[j]);
                }
            }
        }
    }
    
    result[resultIdx] = '\0';
    return result;
}

int main() {
    char title[1000];
    fgets(title, sizeof(title), stdin);
    title[strcspn(title, "\n")] = 0;
    
    char* result = solution(title);
    printf("%s\n", result);
    free(result);
    
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(n)

Single pass through all characters in the string

✓ Linear Growth

Space Complexity

O(1)

Only using variables to track current state, output string not counted

⚡ Linearithmic Space

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Medium Frequency

~5 min Avg. Time

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Input & Output

Constraints

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Related Problems

Common Approaches

Character-by-Character Processing — Algorithm Steps

Visualization

Code -

Time & Space Complexity

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