69. Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

int mySqrt(int x) {    double pre = 0;      double cur = x;           //  这里从x开始 从x/2开始会导致 1 不能满足  x(n+1)= xn - f'(xn)/f(xn)       while(abs(cur - pre) > 0.000001){          pre = cur;          cur = (pre/2 + x/(2*pre));      }      return (int)(cur);}