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.
1 int mySqrt(int x) { 2 int mid,low=1,high=x; 3 if(x<2) 4 return x; 5 while(low<=high){ 6 //如果直接mid=(low+high)/2的话可能会溢出，数字够大的情况下 7 mid=low+(high-low)/2; 8 if(mid==x/mid) break; 9 else if(mid<x/mid) low=mid+1; 10 else high=mid-1; 11 } 12 if(mid>x/mid) 13 return mid-1; 14 else 15 return mid; 16 }
