Implement int sqrt(int x).
Compute and return the square root of x.
x is guaranteed to be a non-negative integer.
Example 1:
Input: 4
Output: 2
Example 2:
Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since we want to return an integer, the decimal part will be truncated.
class Solution {
public int mySqrt(int x) {
long low = 0;
long high = x/2+1;//平方根的值按规律发现不会大于它的中值+1。这样每个查找就少了一次
long tmp;
long mid = 1;
while (low <= high)
{
mid = (low + high) / 2;
tmp = mid * mid;
if (tmp == x)
return (int)mid;
else if (tmp > x)
high = mid - 1;
else if (tmp < x)
low = mid + 1;
}
return (int)high;
}
}
二分法的应用
