C++-蓝桥杯-入门训练

Fibonacci数列,快速幂

 #include <cstdio>
 struct Matrix{int a[][];};
 const int N=,MOD=;
 Matrix A,B,O,I;
 Matrix Mul(Matrix A,Matrix B){
     Matrix C=O;
     for(int i=;i<=N;i++)
         for(int j=;j<=N;j++)
             for(int k=;k<=N;k++)
                 C.a[i][j]=(C.a[i][j]+A.a[i][k]*B.a[k][j])%MOD;
     return C;
 }
 Matrix Pow(Matrix A,int n){
     Matrix B=I;
     for(;n;n>>=,A=Mul(A,A))if(n&)B=Mul(B,A);
     return B;
 }
 int main(){
     for(int i=;i<=;i++)for(int j=;j<=;j++)O.a[i][j]=,I.a[i][j]=(i==j);
     A.a[][]=,A.a[][]=;
     A.a[][]=,A.a[][]=;
     int n;scanf("%d",&n),B=Pow(A,n+),printf("%d\n",B.a[][]);
     return ;
 }

圆的面积

 #include <cmath>
 #include <cstdio>
 typedef double db;
 db r,pi=acos(-);
 int main(){
     scanf("%lf",&r),printf("%.7lf",pi*r*r);
     return ;
 }

序列求和

 #include <cstdio>
 typedef long long ll;
 ll ans,n;
 int main(){
     scanf("%lld",&n),printf("%lld",(+n)*n/);
     return ;
 }

A+B问题

 #include <cstdio>
 int main(){
     int a,b;scanf("%d%d",&a,&b),printf("%d",a+b);
     return ;
 }

数列排序，STL使用

 #include <queue>
 #include <cstdio>
 using namespace std;
 priority_queue<int>q;
 int main(){
     int n,a;scanf("%d",&n);
     for(int i=;i<=n;i++)scanf("%d",&a),q.push(-a);
     for(int i=;i<=n;i++)printf("%d ",-q.top()),q.pop();
     return ;
 }

十六进制转八进制，进制转化

 #include <cstdio>
 #include <string>
 #include <cstring>
 #include <iostream>
 using namespace std;
 char s[];
 int main(){
     int n,len,num,ok;scanf("%d",&n);
     for(int i=;i<=n;i++){
         scanf("%s",s+),len=strlen(s+);
         string ans="";
         for(int i=;i<=len;i++)
             switch(s[i]){
                 case '':ans+="";break;case '':ans+="";break;
                 case '':ans+="";break;case '':ans+="";break;
                 case '':ans+="";break;case '':ans+="";break;
                 case '':ans+="";break;case '':ans+="";break;
                 case '':ans+="";break;case '':ans+="";break;
                 case 'A':ans+="";break;case 'B':ans+="";break;
                 case 'C':ans+="";break;case 'D':ans+="";break;
                 case 'E':ans+="";break;case 'F':ans+="";break;
             }//printf("%s\n",ans.c_str());
         switch(len%){
             case :ans=""+ans;break;
             case :ans=""+ans;break;
         }
         len=ans.length();ok=;
         for(int i=;i<len;i+=){
             num=*(ans[i]-'')+*(ans[i+]-'')+(ans[i+]-'');//printf("%c %c %c\n",ans[i],ans[i+1],ans[i+2]);
             if(num)ok=;if(ok)putchar(num+'');
         }
         puts("");
     }
     return ;
 }

阶乘计算，高精度

 #include <cstdio>
 #include <string>
 #include <cstring>
 #include <cstdlib>
 using namespace std;
 const int MAXN=;
 char buf[MAXN];
 struct BigData{
     int a[MAXN],cnt;
     void init(int c){cnt=c,memset(a,,sizeof(a));}
     void Print(){for(int i=cnt;i>=;i--)putchar(a[i]+'');puts("");}
     void ReadInt(int x){
         memset(buf,,sizeof(buf));
         itoa(x,buf+,);
         init(strlen(buf+));
         for(int i=;i<=cnt;i++)a[cnt-i+]=buf[i]-'';
     }
 };
 BigData Mul(BigData A,BigData B){
     BigData C;C.init();
     for(int i=;i<=A.cnt;i++)
         for(int j=;j<=B.cnt;j++){
             C.a[i+j-]+=A.a[i]*B.a[j];
             C.a[i+j]+=C.a[i+j-]/;
             C.a[i+j-]%=;
         }
     C.cnt=A.cnt+B.cnt-;
     if(C.a[C.cnt+]>=)C.cnt++;
     while(C.a[C.cnt]==&&C.cnt>)C.cnt--;
     return C;
 }
 BigData Ans,A;
 int main(){
     Ans.init(),Ans.a[]=;
     int n;scanf("%d",&n);
     for(int i=;i<=n;i++)A.ReadInt(i),Ans=Mul(Ans,A);
     Ans.Print();
     return ;
 }