3106-LexicographicallySmallestStringAfterOperationsWithConstraint.go

package main

// 3106. Lexicographically Smallest String After Operations With Constraint
// You are given a string s and an integer k.
// Define a function distance(s1, s2) between two strings s1 and s2 of the same length n as:

// The sum of the minimum distance between s1[i] and s2[i] 
// when the characters from 'a' to 'z' are placed in a cyclic order, for all i in the range [0, n - 1].
//     For example, distance("ab", "cd") == 4, and distance("a", "z") == 1.

// You can change any letter of s to any other lowercase English letter, any number of times.
// Return a string denoting the lexicographically smallest string t you can get after some changes, such that distance(s, t) <= k.

// Example 1:
// Input: s = "zbbz", k = 3
// Output: "aaaz"
// Explanation:
// Change s to "aaaz". The distance between "zbbz" and "aaaz" is equal to k = 3.

// Example 2:
// Input: s = "xaxcd", k = 4
// Output: "aawcd"
// Explanation:
// The distance between "xaxcd" and "aawcd" is equal to k = 4.

// Example 3:
// Input: s = "lol", k = 0
// Output: "lol"
// Explanation:
// It's impossible to change any character as k = 0.

// Constraints:
//     1 <= s.length <= 100
//     0 <= k <= 2000
//     s consists only of lowercase English letters.

import "fmt"

func getSmallestString(s string, k int) string {
    bytes := []byte(s)
    min := func (x, y int) int { if x < y { return x; }; return y; }
    for i := 0; i < len(bytes) && k > 0; i++ {
        distA := min(int(bytes[i]-'a'), int('z'-bytes[i]+1))
        if distA <= k {
            bytes[i] = 'a'
        } else {
            bytes[i] -= byte(k)
        }
        k -= distA
    }
    return string(bytes)
}

func main() {
    // Example 1:
    // Input: s = "zbbz", k = 3
    // Output: "aaaz"
    // Explanation:
    // Change s to "aaaz". The distance between "zbbz" and "aaaz" is equal to k = 3.
    fmt.Println(getSmallestString("zbbz", 3)) // "aaaz"
    // Example 2:
    // Input: s = "xaxcd", k = 4
    // Output: "aawcd"
    // Explanation:
    // The distance between "xaxcd" and "aawcd" is equal to k = 4.
    fmt.Println(getSmallestString("xaxcd", 4)) // "aawcd"
    // Example 3:
    // Input: s = "lol", k = 0
    // Output: "lol"
    // Explanation:
    // It's impossible to change any character as k = 0.
    fmt.Println(getSmallestString("lol", 0)) // "lol"
}