Submission #1521092

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Source Code Expand

#include <cstdio>
#include <algorithm>
#include <vector>
using namespace std;
struct LinearRec{
    int n; 
    const int LOG=31,P=1000000007;
    vector<int> first,trans;
    vector<vector<int> > bin;
    vector<int> Add(vector<int> &a, vector<int> &b){
        vector<int> result(n*2+1,0);
        for(int i=0;i<=n;i++){
            for(int j=0;j<=n;j++){
                if((result[i+j]+=1LL*a[i]*b[j]%P)>=P)result[i+j]-=P;
            }
        }
        for(int i=2*n;i>n;i--){
            for(int j=0;j<n;j++){
                if((result[i-1-j]+=1LL*result[i]*trans[j]%P)>=P)result[i-1-j]-=P;
            }result[i]=0;
        }
        result.erase(result.begin()+n+1,result.end());
        return result;
		}
		LinearRec(vector<int> &first,vector<int> &trans):first(first),trans(trans){
		    n=first.size();
		    vector<int> a(n+1,0);
		    a[1]=1;
		    bin.push_back(a);
		    for(int i=1;i<LOG;i++)bin.push_back(Add(bin[i-1],bin[i-1]));
		}
		int Calc(int k){
		    vector<int> a(n+1,0);
		    a[0]=1;
		    for(int i=0;i<LOG;i++){if(k>>i&1)a=Add(a,bin[i]);}
		    int ret=0;
		    for(int i=0;i<n;i++){
		        if((ret+=1LL*a[i+1]*first[i]%P)>=P)ret-=P;
		    }return ret;
		}
};
int main(){
    int n,k;
    scanf("%d%d",&n,&k);
    vector<int> a(n,1);
    LinearRec Rec(a,a);
    printf("%d\n",Rec.Calc(k));
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:44:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&n,&k);
                        ^

Judge Result