Submission #480803

#	Time	Username	Problem	Language	Result	Execution time	Memory
480803		wiwiho	Fibonacci representations (CEOI18_fib)	C++14	0 / 100	1 ms	460 KiB

fib

#include<bits/stdc++.h>

#define eb emplace_back
#define iter(a) a.begin(), a.end()
#define lsort(a) sort(iter(a))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {\
    for(auto pv : a) b << pv << " ";\
    b << "\n";\
}

using namespace std;

typedef long long ll;

ll MOD = 1000000007;

ll inv(ll a){
    ll b = MOD - 2;
    ll ans = 1;
    while(b > 0){
        if(b & 1) ans = ans * a % MOD;
        a = a * a % MOD;
        b >>= 1;
    }
    return ans;
}

int calc(int a, int b){
    return (b - a) / 2;
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;

    set<int> a;
    a.insert(0);
    ll ans = 1;
    for(int i = 0; i < n; i++){
        int x;
        cin >> x;
        assert(x % 2 == 0 && a.find(x) == a.end());
        auto it = a.lower_bound(x);
        assert(it != a.begin());
        if(it != a.end()){
            ans = ans * inv(calc(*prev(it), *it)) % MOD;
            ans = ans * calc(x, *it) % MOD;
        }
        ans = ans * calc(*prev(it), x) % MOD;
        a.insert(x);
        cout << ans << "\n";
    }

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 20
• Subtask 3: 0 / 15
• Subtask 4: 0 / 10
• Subtask 5: 0 / 15
• Subtask 6: 0 / 35