1881. Maximum Value after Insertion

Problem

Tags: String, Greedy

You are given a very large integer n, represented as a string,​​​​​​ and an integer digit x. The digits in n and the digit x are in the inclusive range [1, 9], and n may represent a negative number.

You want to maximize n's numerical value by inserting x anywhere in the decimal representation of n​​​​​​. You cannot insert x to the left of the negative sign.

• For example, if n = 73 and x = 6, it would be best to insert it between 7 and 3, making n = 763.
• If n = -55 and x = 2, it would be best to insert it before the first 5, making n = -255.

Return a string representing the maximum value of n​​​​​​ after the insertion.

Example 1:

Input: n = "99", x = 9
Output: "999"
Explanation: The result is the same regardless of where you insert 9.

Example 2:

Input: n = "-13", x = 2
Output: "-123"
Explanation: You can make n one of {-213, -123, -132}, and the largest of those three is -123.

Constraints:

• 1 <= n.length <= 10^5
• 1 <= x <= 9
• The digits in n​​​ are in the range [1, 9].
• n is a valid representation of an integer.
• In the case of a negative n,​​​​​​ it will begin with '-'.

Code

JS

// 1881. Maximum Value after Insertion (1/4/53380)
// Runtime: 200 ms (27.12%) Memory: 67.30 MB (25.42%) 

/**
 * @param {string} n
 * @param {number} x
 * @return {string}
 */
var maxValue = function(n, x) {
let u = false;
    if(n[0] == "-") {
        for(let i = 1; i < n.length; i++) {
            if(x - parseInt(n[i]) < 0) {
n = n.split("");
                n.splice(i,0,x);
    n = n.join("");
                u = true;
break;
}
        }
    } else {
        for(let i = 0; i < n.length; i++) {
            if(x - parseInt(n[i]) > 0) {
n = n.split("");
                n.splice(i,0,x);
    n = n.join("");
                u = true;
break;
}
        }
    }
    
    if(!u) return n + String(x);
    
    else return n;
};