# 69. Sqrt(x)
Implement int sqrt(int x)
.
Compute and return the square root of x, where x is guaranteed to be a non-negative integer.
Since the return type is an integer, the decimal digits are truncated and only the integer part of the result is returned.
Example 1:
Input: 4
Output: 2
Example 2:
Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since
the decimal part is truncated, 2 is returned.
# Solution
Approach 1: Binary search.
# Code (Python)
Approach 1:
# Code (C++)
Approach 1:
class Solution {
public:
int mySqrt(int x) {
int head = 0;
int tail = x;
while (head <= tail)
{
long mid = head + (tail - head) / 2;
long square = mid * mid;
if (square == x)
return mid;
else if (square < x)
head = mid + 1;
else
tail = mid - 1;
}
return head - 1;
}
};