Question

How to remove odd frequency characters from a string in Rust

Answer 1

use std::collections::HashMap;

fn remove_odd_frequency_characters(s: &str) -> String {
    let mut frequency_map = HashMap::new();
    
    // Count the frequency of each character
    for ch in s.chars() {
        *frequency_map.entry(ch).or_insert(0) += 1;
    }

    // Build the result string excluding characters with odd frequencies
    let mut result = String::new();
    for ch in s.chars() {
        if frequency_map[&ch] % 2 == 0 {
            result.push(ch);
        }
    }

    result
}

fn main() {
    let s = "rust programming version 1.82";
    
    let new_string = remove_odd_frequency_characters(s);
    
    println!("{}", new_string);
}


 
 
/*
run:
 
rsrogrmmingrsion

*/

 

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