2023 rcpc

2023/rcpc/d1/editorial/I. Weird Divisibility.cpp

@@ -0,0 +1,58 @@
+/// Gheorghies Alexandru 
+#include<bits/stdc++.h>
+
+using namespace std;
+typedef long long ll;
+typedef pair<ll,ll> pll;
+const ll NMAX=1e5+5;
+ll primes[NMAX],divisors[NMAX],cntp=0,cntdiv=0;
+bool sieve[NMAX];
+void AddDivisors(ll base, ll exponent){
+    ll n=cntdiv,curr=1;
+    for(ll j=1;j<=exponent;j++){
+        curr*=base;
+        for(ll i=0;i<n;i++){
+            divisors[cntdiv++]=divisors[i]*curr;
+        }
+    }
+}
+map<ll,ll> cache;
+void tc(){
+    ll n,cpy;
+    cin>>n;
+    if(cache.count(n)){
+        cout<<cache[n]<<'\n';
+        return;
+    }
+    cpy=n;
+    divisors[0]=1;
+    cntdiv=1;
+    for(ll i=0;primes[i]*primes[i]<=n;i++){
+        ll e=0;
+        while(n%primes[i]==0) n/=primes[i],e++;
+        if(e) AddDivisors(primes[i],e*2);
+    }
+    if(n) AddDivisors(n,2);
+    ll ans=LLONG_MAX;
+    for(ll i=0;i<cntdiv;i++){
+        if(divisors[i]>cpy){
+            ans=min(ans,divisors[i]);
+        }
+    }
+    cache[cpy]=ans-cpy;
+    cout<<ans-cpy<<'\n';
+}
+int main()
+{
+    for(ll i=2;i<NMAX;i++){
+        if(!sieve[i]){
+            primes[cntp++]=i;
+            for(ll j=i*i;j<NMAX;j+=i)
+                sieve[j]=1;
+        }
+    }
+    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
+    ll t; cin>>t; while(t--)
+        tc();
+    return 0;
+}