C++程序检查给定数字是否互质
假设,我们在一个数组nums中有n个整数。我们需要找出数组中的数字是成对互质、集合互质还是不互质。
如果gcd(nums[i], nums[j]) = 1,则称两个数字nums[i]和nums[j]为成对互质。这应该适用于数组中的每一对数字,并且i < j。
如果gcd(nums[i]) = 1,则称这些数字为集合互质。
如果它们既不是成对互质也不是集合互质,我们就说它们不互质。
因此,如果输入类似于n = 4,nums = {7, 11, 13, 17},则输出将是这些数字是成对互质的。
如果我们检查数组中的每一对数字,它们的gcd将始终为1。
为了解决这个问题,我们将遵循以下步骤:
Define an array fac of size: 100 initialized with 0s. Define an array checkPrime of size: 100 initialized with 0s. gcdVal := 0 for initialize i := 0, when i < n, update (increase i by 1), do: gcdVal := gcd of (nums[i], gcdVal) (increase fac[nums[i]] by 1) if gcdVal is same as 1, then: pw := true for initialize k := 2, when k < 100, update (increase k by 1), do: if checkPrime[k] is non-zero, then: Ignore following part, skip to the next iteration c := 0 for initialize j := k, when j < 100, update j := j + k, do: c := c + fac[j] checkPrime[j] := true pw := pw AND true if c <= 1 if pw is non-zero, then: print("The numbers are pairwise coprime") Otherwise print("The numbers are setwise coprime") Otherwise print("The numbers are not coprime")
示例
让我们看看下面的实现,以便更好地理解:
#include <bits/stdc++.h> using namespace std; void solve(int n, int nums[]){ int fac[100] = {0}; bool checkPrime[100] = {0}; int gcdVal = 0; for(int i = 0; i < n ; i++) { gcdVal = __gcd(nums[i], gcdVal); ++fac[nums[i]]; } if(gcdVal == 1) { bool pw = true; for(int k = 2; k < 100; ++k) { if(checkPrime[k]) continue; int c = 0; for(int j = k; j < 100; j += k) { c += fac[j]; checkPrime[j] = true; } pw = pw && c <= 1; } if(pw) cout<< "The numbers are pairwise coprime"; else cout<< "The numbers are setwise coprime"; } else cout << "The numbers are not coprime"; } int main() { int n = 4, nums[] = {7, 11, 13, 17}; solve(n, nums); return 0; }
输入
4, {7, 11, 13, 17};
输出
The numbers are pairwise coprime
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