在两个半部中所有长度相等的n的所有可能二进制数?
在这里,我们将看到所有可能的n位二进制数(n由用户给出),其中每半的总和是相同的。例如,如果数字为10001,则10和01相同,因为它们的总和相同,并且分别位于不同的一半。在这里,我们将生成该类型的所有数字。
算法
genAllBinEqualSumHalf(n,左,右,diff)
左和右最初是空的,diff保持左和右之间的差异
Begin if n is 0, then if diff is 0, then print left + right end if return end if if n is 1, then if diff is 0, then print left + 0 + right print left + 1 + right end if return end if if 2* |diff| <= n, then if left is not blank, then genAllBinEqualSumHalf(n-2, left + 0, right + 0, diff) genAllBinEqualSumHalf(n-2, left + 0, right + 1, diff-1) end if genAllBinEqualSumHalf(n-2, left + 1, right + 0, diff + 1) genAllBinEqualSumHalf(n-2, left + 1, right + 1, diff) end if End
示例
#include <bits/stdc++.h> using namespace std; //左右字符串将被填充,di将保留左右之间的差异 void genAllBinEqualSumHalf(int n, string left="", string right="", int di=0) { if (n == 0) { //when the n is 0 if (di == 0) //if diff is 0, then concatenate left and right cout << left + right << " "; return; } if (n == 1) {//if 1 bit number is their if (di == 0) { //when difference is 0, generate two numbers one with 0 after left, another with 1 after left, then add right cout << left + "0" + right << " "; cout << left + "1" + right << " "; } return; } if ((2 * abs(di) <= n)) { if (left != ""){ //numbers will not start with 0 genAllBinEqualSumHalf(n-2, left+"0", right+"0", di); //在左右后加0- genAllBinEqualSumHalf(n-2, left+"0", right+"1", di-1); //在左后加0,在右后加1,所以相差少1- } genAllBinEqualSumHalf(n-2, left+"1", right+"0", di+1); //add 1 after left, and 0 after right, so difference is 1 greater genAllBinEqualSumHalf(n-2, left+"1", right+"1", di); //add 1 after left and right } } main() { int n = 5; genAllBinEqualSumHalf(n); }
输出结果
100001 100010 101011 110011 100100 101101 101110 110101 110110 111111