基于 DFA 的除法\n
确定性有限自动机 (DFA) 用于检查一个数字是否可以被另一个数字 k 整除。如果不能整除,那么此算法还将找到余数。
对于基于 DFA 的除法,首先,我们必须找到 DFA 的转换表,使用该表,我们可以轻松找到答案。在 DFA 中,每个状态只有两个转换,即 0 和 1。
输入和输出
Input: The number: 50 and the divisor 3 Output: 50 is not divisible by 3 and remainder is: 2
算法
dfaDivision(num, k)
输入:一个数字 num 和除数 k。
输出:检查可除性和余数。
Begin create transition table of size k * 2 //2 for transition 0 and 1 state = 0 checkState(num, state, table) return state End
checkState(num, state, table)
输入:一个数字 num、状态和转换表。
输出:在执行除法后更新状态。
Begin if num ≠ 0, then tempNum := right shift number for i bit checkState(tempNum, state, table) index := number AND 1 //perform logical and with number and 1 state := table[state][index] End
示例
#include <iostream> using namespace std; void makeTransTable(int n, int transTable[][2]) { int zeroTrans, oneTrans; for (int state=0; state<n; ++state) { zeroTrans = state<<1; //next state for bit 0 transTable[state][0] = (zeroTrans < n)? zeroTrans: zeroTrans-n; oneTrans = (state<<1) + 1; //next state for bit 1 transTable[state][1] = (oneTrans < n)? oneTrans: oneTrans-n; } } void checkState(int num, int &state, int Table[][2]) { if (num != 0) { //shift number from right to left until 0 checkState(num>>1, state, Table); state = Table[state][num&1]; } } int isDivisible (int num, int k) { int table[k][2]; //create transition table makeTransTable(k, table); //fill the table int state = 0; //initially control in 0 state checkState(num, state, table); return state; //final and initial state must be same } int main() { int num; int k; cout << "Enter Number, and Divisor: "; cin >> num>> k; int rem = isDivisible (num, k); if (rem == 0) cout<<num<<" is divisible by "<<k; else cout<<num<<" is not divisible by "<<k<<" and remainder is: " << rem; }
输出
Enter Number, and Divisor: 50 3 50 is not divisible by 3 and remainder is: 2
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