2109-AddingSpacesToAString.go

package main

// 2109. Adding Spaces to a String
// You are given a 0-indexed string s and a 0-indexed integer array spaces 
// that describes the indices in the original string where spaces will be added. 
// Each space should be inserted before the character at the given index.
//     For example, given s = "EnjoyYourCoffee" and spaces = [5, 9], we place spaces before 'Y' and 'C', which are at indices 5 and 9 respectively. 
//     Thus, we obtain "Enjoy Your Coffee".

// Return the modified string after the spaces have been added.

// Example 1:
// Input: s = "LeetcodeHelpsMeLearn", spaces = [8,13,15]
// Output: "Leetcode Helps Me Learn"
// Explanation: 
// The indices 8, 13, and 15 correspond to the underlined characters in "LeetcodeHelpsMeLearn".
// We then place spaces before those characters.

// Example 2:
// Input: s = "icodeinpython", spaces = [1,5,7,9]
// Output: "i code in py thon"
// Explanation:
// The indices 1, 5, 7, and 9 correspond to the underlined characters in "icodeinpython".
// We then place spaces before those characters.

// Example 3:
// Input: s = "spacing", spaces = [0,1,2,3,4,5,6]
// Output: " s p a c i n g"
// Explanation:
// We are also able to place spaces before the first character of the string.

// Constraints:
//     1 <= s.length <= 3 * 10^5
//     s consists only of lowercase and uppercase English letters.
//     1 <= spaces.length <= 3 * 10^5
//     0 <= spaces[i] <= s.length - 1
//     All the values of spaces are strictly increasing.

import "fmt"

func addSpaces(s string, spaces []int) string {
    arr := make([]byte, 0, len(s) + len(spaces))
    for si, spacesi := 0, 0; si < len(s); si++ {
        if spacesi < len(spaces) && si == spaces[spacesi] {
            arr = append(arr, ' ')
            spacesi++
        }
        arr = append(arr, s[si])
    }
    return string(arr)
}

func addSpaces1(s string, spaces []int) string {
    arr, index := make([]byte, 0), 0
    for _, v := range spaces {
        arr = append(arr, []byte(s)[index:v]...)
        arr = append(arr, ' ')
        index = v
    }
    arr = append(arr, []byte(s)[index:]...)
    return string(arr)
}

func main() {
    // Example 1:
    // Input: s = "LeetcodeHelpsMeLearn", spaces = [8,13,15]
    // Output: "Leetcode Helps Me Learn"
    // Explanation: 
    // The indices 8, 13, and 15 correspond to the underlined characters in "LeetcodeHelpsMeLearn".
    // We then place spaces before those characters.
    fmt.Println(addSpaces("LeetcodeHelpsMeLearn", []int{8,13,15})) // "Leetcode Helps Me Learn"
    // Example 2:
    // Input: s = "icodeinpython", spaces = [1,5,7,9]
    // Output: "i code in py thon"
    // Explanation:
    // The indices 1, 5, 7, and 9 correspond to the underlined characters in "icodeinpython".
    // We then place spaces before those characters.
    fmt.Println(addSpaces("icodeinpython", []int{1,5,7,9})) // "i code in py thon"
    // Example 3:
    // Input: s = "spacing", spaces = [0,1,2,3,4,5,6]
    // Output: " s p a c i n g"
    // Explanation:
    // We are also able to place spaces before the first character of the string.
    fmt.Println(addSpaces("spacing", []int{0,1,2,3,4,5,6})) // " s p a c i n g"

    fmt.Println(addSpaces1("LeetcodeHelpsMeLearn", []int{8,13,15})) // "Leetcode Helps Me Learn"
    fmt.Println(addSpaces1("icodeinpython", []int{1,5,7,9})) // "i code in py thon"
    fmt.Println(addSpaces1("spacing", []int{0,1,2,3,4,5,6})) // " s p a c i n g"
}