Question

How to reverse subarray of an array in JavaScript

Answer 1

function reverseSubarray(arr, start, end) {
	if (end > arr.length) {
       	console.log("End index out of range");
        return;
    }
      
    const mid_sub = (end - start + 1) / 2;  
      
    for (let i = 0; i < mid_sub; i++) {
         let tmp = arr[start + i];
         arr[start + i] = arr[end - i];
         arr[end - i] = tmp;      
    }
}


const arr = [ 1, 4, 8, 0, 7, 3, 9, 5, 6 ];
         
const start = 2, end = 6;
         
reverseSubarray(arr, start, end);
  
console.log(arr);


  
  
  
  
/*
run:
  
[1, 4, 9, 3, 7, 0, 8, 5, 6]
  
*/

 

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