Submission #134465

#	Time	Username	Problem	Language	Result	Execution time	Memory
134465		dragonslayerit	Fibonacci representations (CEOI18_fib)	C++14	50 / 100	4030 ms	1828 KiB

fib

#include <cstdio>
#include <set>
#include <array>

const int MOD=1e9+7;

std::set<int> zk;

void increment(int A){
  if(A==-1) return;
  if(A==0) A=1;
  if(zk.count(A+1)){
    zk.erase(A+1);
    increment(A+2);
  }else if(zk.count(A-1)){
    zk.erase(A-1);
    increment(A+1);
  }else if(zk.count(A)){
    zk.erase(A);
    increment(A-2);
    increment(A+1);
  }else{
    zk.insert(A);
  }
}

int main(){
  int N;
  scanf("%d",&N);
  for(int i=0;i<N;i++){
    int A;
    scanf("%d",&A);
    increment(A);
    int prev=0;
    std::array<int,2> dp={0,1};
    //dp[0]=number of ways where prev-1 is used but prev is not
    //dp[1]=number of ways where prev is used but prev+1 is not
    for(int x:zk){
      dp={(((x-prev)/2)*1LL*dp[0]+((x-prev-1)/2)*1LL*dp[1])%MOD,(dp[0]+dp[1])%MOD};
      prev=x;
    }
    printf("%d\n",(dp[0]+dp[1])%MOD);
  }
}

Compilation message (stderr)

fib.cpp: In function 'int main()':
fib.cpp:39:60: warning: narrowing conversion of '((((((long long int)((x - prev) / 2)) * 1) * ((long long int)dp.std::array<int, 2>::operator[](0))) + ((((long long int)(((x - prev) - 1) / 2)) * 1) * ((long long int)dp.std::array<int, 2>::operator[](1)))) % 1000000007)' from 'long long int' to 'int' inside { } [-Wnarrowing]
       dp={(((x-prev)/2)*1LL*dp[0]+((x-prev-1)/2)*1LL*dp[1])%MOD,(dp[0]+dp[1])%MOD};
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
fib.cpp:29:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&N);
   ~~~~~^~~~~~~~~
fib.cpp:32:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&A);
     ~~~~~^~~~~~~~~

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