Question

How to find a number in a vector that appears once in Rust

Answer 1

fn number_exist_few_times(arr: &[i32], number: i32, index: usize) -> bool {
    for (i, &item) in arr.iter().enumerate() {
        if item == number && i != index {
            return true;
        }
    }
    
    false
}

fn get_single_number(arr: &[i32]) -> i32 {
    for (i, &item) in arr.iter().enumerate() {
        if !number_exist_few_times(arr, item, i) {
            return item;
        }
    }
    
    -1
}

fn main() {
    let arr = vec![3, 2, 1, 2, 3, 3, 1, 5, 9, 7, 7, 9, 9];
    
    println!("{}", get_single_number(&arr));
}


      
/*
run:
  
5
 
*/
 

 

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