編程演算法 - 醜數 代碼(C)

標籤：mystra   編程演算法   醜數   代碼   c   

醜數 代碼(C)

本文地址: http://blog.csdn.net/caroline_wendy

題目: 我們把只包含因子2, 3 和 5的數稱作醜數. 求按從小到大的順序的第5個醜數.

可以設定一個數組包含所需要的醜數, 依次比較乘以2, 乘以3, 乘以5的最小的數, 最後返回結果.

如第5個醜數是5, 如1, 2, 3, 4(2*2), 5均是醜數.

代碼:

/* * main.cpp * *  Created on: 2014.6.12 *      Author: Spike *//*eclipse cdt, gcc 4.8.1*/#include <stdio.h>#include <stdlib.h>#include <string.h>int Min(int number1, int number2, int number3) {int min = (number1 < number2) ? number1 : number2;min = (min < number3) ? min : number3;return min;}int GetUglyNumber(int index) {if (index <= 0)return 0;int* pUglyNumbers = new int[index];pUglyNumbers[0] = 1;int nextUglyIndex = 1;int* pMultiply2 = pUglyNumbers;int* pMultiply3 = pUglyNumbers;int* pMultiply5 = pUglyNumbers;while (nextUglyIndex < index) {int min = Min(*pMultiply2*2, *pMultiply3*3, *pMultiply5*5);pUglyNumbers[nextUglyIndex] = min;while (*pMultiply2*2 <= pUglyNumbers[nextUglyIndex])++pMultiply2;while (*pMultiply3*3 <= pUglyNumbers[nextUglyIndex])++pMultiply3;while (*pMultiply5*5 <= pUglyNumbers[nextUglyIndex])++pMultiply5;++nextUglyIndex;}int ugly = pUglyNumbers[nextUglyIndex-1];delete[] pUglyNumbers;return ugly;}int main(void){    int num = 5;    int result = GetUglyNumber(num);    printf("result = %d\n", result);    return 0;}

輸出:

result = 5