c_cpp 斐波那契

Posted 2021-05-14

#include<bits/stdc++.h>
using namespace std;

int fibBU(int n);
int fib(int n);
int fib(int n, map<int,int> &memo);

int main(){
    //freopen("ip.txt","r",stdin);
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        cout<<"Memoization: "<<fib(n)<<endl;
        cout<<"BottomUp: "<<fibBU(n)<<endl;
    }
    return 0;
}

// Memoization
int fib(int n){
    map<int,int> memo;
    return fib(n,memo);
}
int fib(int n, map<int,int> &memo){
    if(n==1 || n==2){
        return 1;
    }
    if(memo.find(n)!=memo.end()){
        return memo[n];
    }
    memo[n]=fib(n-1)+fib(n-2);
    return memo[n];
}

// BottomUp
int fibBU(int n){
    vector<int> BU(n+1);
    for(int i=1;i<=n;i++){
        if(i==1 || i==2){
            BU[i]=1;
        }else{
            BU[i]=BU[i-1]+BU[i-2];
        }
    }
    return BU[n];
}