Submission #480807

#	Time	Username	Problem	Language	Result	Execution time	Memory
480807		wiwiho	Fibonacci representations (CEOI18_fib)	C++14	0 / 100	3 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;
}
 
ll solve(vector<int> a){
    lsort(a);
    
    vector<int> cnt(501);
    for(int i : a) cnt[i]++;
    cnt[2] += cnt[1] / 2;
    cnt[1] %= 2;
    for(int i = 1; i + 2 <= 500; i++){
        int t = min(cnt[i], cnt[i + 1]);
        cnt[i] -= t;
        cnt[i + 1] -= t;
        cnt[i + 2] += t;
    }
 
    for(int i = 500; i - 2 >= 1; i--){
        if(cnt[i] > 2) return 0;
        if(cnt[i] <= 1) continue;
        cnt[i - 1]++;
        cnt[i - 2]++;
        cnt[i] = 1;
    }
    if(cnt[1] > 1 || cnt[2] > 1) return 0;
    //for(int i = 1; i <= 20; i++) cerr << cnt[i] << " ";
    //cerr << "\n";
 
    vector<int> dp(501);
    dp[0] = 1;
    for(int i = 499; i >= 0; i--){
        for(int j = i + 1; j <= 500; j++){
            if(i % 2 != j % 2){
                if(cnt[i + 1] == 0 || j == i + 1) dp[0] += dp[j];
                dp[0] %= MOD;
                if(cnt[i] == 1) dp[j] = 0;
            }
        }
        if(cnt[i] == 1){
            dp[i] = dp[0];
            dp[0] = 0;
        }
        //if(i > 20) continue;
        //cerr << "dp " << i << "  ";
        //for(int j = 0; j <= 20; j++) cerr << dp[j] << " ";
        //cerr << "\n";
    }
 
    return dp[0];
}
 
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
 
    int n;
    cin >> n;
    assert(n <= 100);
 
    vector<int> a;
    for(int i = 0; i < n; i++){
        int x;
        cin >> x;
        assert(x <= 100);
        a.eb(x);
        cout << solve(a) << "\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