SQRT (x) && 367. Valid Perfect Square

SQRT (x) Implement int sqrt(int x).

Compute and return the square root of X.

Hide TagsBinary Search MathHide Similar Problems(M) Pow (x, N) (m) Valid Perfect SquareTime Limit exceed solution if start from 0.

 Public classSolution { Public intMYSQRT (intx) {if(x = = 0)            return0; intLowerbound = 1; intHigherbound = 2; //search for a boundary         while(true) {          intSquare = Lowerbound *lowerbound; if(Square = =x)returnlowerbound; if(Square <x) {lowerbound=Higherbound; Higherbound= Higherbound * 2; } Else{lowerbound= LOWERBOUND/2; Higherbound= HIGHERBOUND/2;  Break; }        }            intleft = lowerbound + 1; intright = HigherBound-1;  while(Left <=Right ) {          intMid = (left + right)/2; intSquare = Mid *mid; if(Square = =x)returnmid;          if(Square <x) left= Mid + 1; Else Right= Mid-1; }        returnLeft-1; }}

Another solution if start from both ends of Integer range.

 Public classSolution { Public intMYSQRT (intx) {if(x = = 0)            return0; intleft = 1, right =Integer.max_value;  while(Left <=Right ) {            intMid = left + (right-left)/2; inttemp = X/mid;//Use division because mid*mid may > Integer.max            if(Mid = =temp)returnmid; if(Mid >temp) Right= Mid-1; Else Left= Mid + 1; }        returnLeft-1; }}

367. Valid Perfect Square

Given a positive integer num, write a function which returns True if num is a perfect square else False.

Note:do no built-in library function such as sqrt .

Example 1:

Input:16returns:true

Example 2:

Input:14returns:false 

Hide TagsBinary Search MathHide Similar Problems(M) Sqrt (x)

 Public classSolution { Public BooleanIsperfectsquare (intnum) {        if(num = = 0)            return true; intleft = 1, right =Integer.max_value;  while(Left <=Right ) {            intMid = left + (right-left)/2; inttemp = Num/mid;//Use division because mid*mid may > Integer.max            if(Mid = =temp) {                if(Mid*mid = =num)return true; return false;//Here is the trap! e.g. num = 5, mid = 2            }            if(Mid >temp) Right= Mid-1; Else Left= Mid + 1; }        return false; }}

SQRT (x) && 367. Valid Perfect Square