2022-07-02
Description
Given a non-negative integer x
, compute and return the square root of x
.
Since the return type is an integer, the decimal digits are truncated, and only the integer part of the result is returned.
Note: You are not allowed to use any built-in exponent function or operator, such as pow(x, 0.5)
or x ** 0.5
.
Example 1:
Input: x = 4
Output: 2
Example 2:
Input: x = 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since the decimal part is truncated, 2 is returned.
Constraints:
0 <= x <= 2^31 - 1
Solution
Approach #0: Binary Search
func mySqrt(x int) (ans int) {
l, r := 0, x
for l <= r {
mid := l + (r-l)/2
if mid*mid <= x {
ans = mid
l = mid + 1
} else {
r = mid - 1
}
}
return
}
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