1五、【常見算法】實現sqrt函數

問題：手寫代碼實現sqrt函數，即求一個整數的平方根

分析：二分查找思想

 1 #include <iostream>
 2  3 using namespace std;  4  5 int sqrt(int x)  6 {  7 long left = 0;  8  9 if(x == 1) 10 return 1; 11 long right = x; 12 13 long mid = left + (right - left)/2; 14 while(left + 1 < right) 15  { 16 if(x > mid * mid) 17  { 18 left = mid; 19  } 20 else if(x < mid * mid) 21  { 22 right = mid; 23  } 24 else 25  { 26 return mid; 27  } 28 mid = left + (right - left)/2; 29  } 30 return left; 31 } 32 33 int main() 34 { 35 cout << "144 的平方根爲：" << sqrt(144) << endl; 36 return 0; 37 }