README_EN.md

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difficulty	Easy
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tags	JavaScript

2796. Repeat String 🔒

中文文档

Description

Write code that enhances all strings such that you can call the string.replicate(x) method on any string and it will return repeated string x times.

Try to implement it without using the built-in method string.repeat.

 

Example 1:

Input: str = "hello", times = 2
Output: "hellohello"
Explanation: "hello" is repeated 2 times

Example 2:

Input: str = "code", times = 3
Output: "codecodecode"
Explanation: "code" is repeated 3 times

Example 3:

Input: str = "js", times = 1
Output: "js"
Explanation: "js" is repeated 1 time

 

Constraints:

• 1 <= times <= 105
• 1 <= str.length <= 1000

 

Follow up: Let's assume, for the sake of simplifying analysis, that concatenating strings is a constant time operation O(1). With this assumption in mind, can you write an algorithm with a runtime complexity of O(log n)?

Solutions

Solution 1

TypeScript

declare global {
    interface String {
        replicate(times: number): string;
    }
}

String.prototype.replicate = function (times: number) {
    return new Array(times).fill(this).join('');
};

JavaScript

String.prototype.replicate = function (times) {
    return Array(times).fill(this).join('');
};