Question

How to get the square root rounded down to the nearest integer of a positive integer in C#

Answer 1

using System;

public class Program
{
	public static int mySqrt(int n) {
		if (n == 0 || n == 1) {
			return n;
		}

		int start = 1;
		int end = n;

		while (start <= end) {
			int mid = start + (end - start) / 2;
			if ((long)mid * mid > (long)n) {
				end = mid - 1;
			}
			else if (mid * mid == n) {
				return mid;
			} 
			else {
				start = mid + 1;
			}
		}

		return end;
	}

	public static void Main(string[] args)
	{
		Console.WriteLine(mySqrt(240000)); // 489.897
	}
}




/*
run:

489

*/

 

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