【HDU6216】 A Cubic number and A Cubic Number 和广工的加强版

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【HDU6216】 A Cubic number and A Cubic Number 和广工的加强版

题目传送门_杭电版题目传送门_广工版广工版的是杭电版的加强版. 题意:判断一个质数是否是两个整数的立方差 ---- 数学题题解: 根据立方差公式:\(a^3 - b^3 = (a - b)(a^2 + ab + b^2)\) 且 p 为质数所以 \((a - b)(a^2 + ab + b^2)\) 其中任意一括号为 1,另一括号则为 p. 经计算检验(这里就不写啦),得 \((a - b) = 1\),\((a^2 + ab + b^2) = p\) . 因为\((a - b) = 1…

hdu 6216 A Cubic number and A Cubic Number【数学题】

hdu 6216 A Cubic number and A Cubic Number[数学] 题意:判断一个素数是否是两个立方数之差,就是验差分.. 题解:只有相邻两立方数之差才可能,,因为x^3-y^3=(x-y)(x^2+xy+y^2),看(x-y),就能很快想到不相邻的立方数之差是不可能是素数的:),,然后把y=x+1代入,得:p=3x^2+3x+1,所以可得判断条件为:①p-1必须能被3整除:②(p-1)/3必须能表示为两个相邻整数之积. #include<iostream> #inc…

2017青岛网络赛1011 A Cubic number and A Cubic Number

A Cubic number and A Cubic Number Time Limit: 1000/1000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others) Total Submission(s): 4947 Accepted Submission(s): 1346 Problem Description A cubic number is the result of using a whole number i…

[Javascript] Use Number() to convert to Number if possilbe

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Ugly Number,Ugly Number II,Super Ugly Number

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263. Ugly Number 注意:1.小于等于0都不属于丑数 2.while循环的判断不是num >= 0, 而是能被2 .3.5整除,即能被整除才去除这些数 class Solution { public: bool isUgly(int num) { ) return false; == ) num /= ; == ) num /= ; == ) num /= ; ? true : false; } }; 264. Ugly Number II 用一个数组去存第n个前面的所有整数,然后…