Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Returns: True Example 2: Input: 14 Returns: False Credits:Speci…

Typical binary search.. but take care of data overflow if you are using C++ class Solution { public: bool isPerfectSquare(int num) { ) return false; ) return true; , j = num - ; while(i <= j) { ; long long r = mid * mid; if(r == num) return true; ; ;…

Leetcode之二分法专题-367. 有效的完全平方数(Valid Perfect Square) 给定一个正整数 num,编写一个函数,如果 num 是一个完全平方数,则返回 True,否则返回 False. 说明:不要使用任何内置的库函数,如  sqrt. 示例 1: 输入:16 输出:True 示例 2: 输入:14 输出:False 不能用sqrt,判断一个数是否是一个完全平方数. 1.可以用for循环,但时间复杂度高2.用二分法,思路如下: 从0-N,取中点 看中点的平方是否大于nu…

367. Valid Perfect Square Easy Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Output: true Example 2: Input: 1…

原题: 367. Valid Perfect Square 读题: 求一个整数是否为完全平方数,如1,4,9,16,……就是完全平方数,这题主要是运算效率问题 求解方法1:812ms class Solution { public: bool isPerfectSquare(int num) { if(num < 0) return false; int i = 0; //这里要加1,不然num = 1时会出错 for(;i< num/2 + 1;i++) { if(i*i == num) {…

Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Returns: True Example 2: Input: 14 Returns: False 题意: 验证完全平方数 思…

Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Returns: True Example 2: Input: 14 Returns: False Credits:Speci…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 方法一:完全平方式性质 方法二:暴力求解 方法三:二分查找 方法四:牛顿法 日期 题目地址:https://leetcode.com/problems/valid-perfect-square/description/ 题目描述 Given a positive integer num, write a function which returns…

Given a positive integer num, write a function which returns True if num is a perfect square else False. Note: Do not use any built-in library function such as sqrt. Example 1: Input: 16 Returns: True Example 2: Input: 14 Returns: False 本题可以用binary s…

题目描述: Given a positive integer num, write a function which returns True if num is a perfect square else False. 解题分析: 这种找数字的题一般都用类似与二分查找的算法.需要注意的是比较平方和时考虑到integer溢出的情况.所以这个结果是要用Long类型保存.由此到来的改变是判断相等时要用“equals()”方法,而不是“==”. 实现代码: public class Solution…