1 solutions

  • 0
    @ 2022-3-30 21:39:06

    核心:(a / b) % p = (a * b ^p-2^ ) % p​

    #include<bits/stdc++.h>
    using namespace std;
    #define ll long long
    ll n;
    const ll mod=1e9+7;
    
    ll ksm(ll x, ll n){
    	x %= mod;
    	ll res = 1;
    	while(n > 0){
    		if(n&1) res = ((res%mod) * (x%mod))%mod;
    		x = ((x%mod) * (x%mod))%mod;
    		n >>= 1; 
    	}
    	return res%mod;
    }
    
    int main(){
    	cin >> n;
    	cout << (ksm(n, mod-2) % mod);	
    	return 0;
    }
    

    Information

    ID
    1550
    Time
    1000ms
    Memory
    256MiB
    Difficulty
    2
    Tags
    # Submissions
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    Accepted
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