LeetCode-in-Java
2109. Adding Spaces to a String
Medium
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"andspaces = [5, 9], we place spaces before'Y'and'C', which are at indices5and9respectively. Thus, we obtain"Enjoy **Y**our **C**offee".
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 * 105sconsists only of lowercase and uppercase English letters.1 <= spaces.length <= 3 * 1050 <= spaces[i] <= s.length - 1- All the values of
spacesare strictly increasing.
Solution
public class Solution {
public String addSpaces(String string, int[] spaces) {
char[] stringChars = new char[string.length() + spaces.length];
for (int i = 0; i < spaces.length; i++) {
stringChars[spaces[i] + i] = ' ';
}
int equivalentIndex = -1;
int i = 0;
while (i < string.length()) {
equivalentIndex++;
if (stringChars[equivalentIndex] == ' ') {
i--;
} else {
stringChars[equivalentIndex] = string.charAt(i);
}
i++;
}
return new String(stringChars);
}
}