快排&归并&二分查找

来源：互联网发布：阿里云研发团队人数编辑：程序博客网时间：2024/04/29 16:07
算法实验：
#include<iostream>#include<cstring>#include<cmath>#include<ctime>#include<cstdlib>#include<algorithm>#include<iomanip>#include<fstream>#include<map>using namespace std;const int MAXN=1e5;int n,lb,ub;int a[MAXN],b[MAXN];int menu(){    cout<<"选项："<<endl;    cout<<"1、 生成随机数据"<<endl;    cout<<"2、 快速排序"<<endl;    cout<<"3、 归并排序"<<endl;    cout<<"4、 排序后二分查找"<<endl;    cout<<"5、 打印结果"<<endl;    cout<<"6、 退出系统"<<endl;    cout<<"请选择：";    int op;    cin>>op;    if(op==1) return 1;    else if(op==2) return 2;    else if(op==3) return 3;    else if(op==4) return 4;    else if(op==5) return 5;    else if(op==6) return 6;    else return 7;}void gen(){    srand((unsigned)time(NULL));    cout<<"请输入数据个数：";    cin>>n;    cout<<"请输入数据下限：";    cin>>lb;    cout<<"请输入数据上限：";    cin>>ub;    for(int i=1;i<=n;i++)    {        a[i]=lb+rand()%(ub-lb+1);    }}void print(){    for(int i=1;i<=n;i++)    {        cout<<a[i]<<" ";        if(!(i%10)) cout<<endl;    }    cout<<endl<<endl;}/*void quicksort1(int i,int j){    int m,n,tmp;    int k;    m=i;    n=j;    k=a[(i+j)/2];    while(m<=n)    {        while(a[m]<k&&m<j) m++;        while(a[n]>k&&n>i) n--;        if(m<=n)        {            tmp=a[m];            a[m]=a[n];            a[n]=tmp;            m++;            n--;        }        if(m<j) quicksort(m,j);        if(n>i) quicksort(i,n);    }}*/int Partition(int p,int r){    int i=p,j=r+1;    int x=a[p];    while(true)    {        while(a[++i]>x);        while(a[--j]<x);        if(i>=j) break;        swap(a[i],a[j]);    }    a[p]=a[j];    a[j]=x;    return j;}void quicksort(int p,int r){    if(p<r)    {        int q=Partition(p,r);        quicksort(p,q-1);        quicksort(q+1,r);    }}void Merge(int low,int mid,int high){    int s=low,t=mid+1,k=low;    while(s<=mid&&t<=high)    {        if(a[s]>a[t])        {            b[k]=a[s];            s++;        }else        {            b[k]=a[t];            t++;        }        k++;    }    if(s==mid+1)    {        for(int i=k;i<=high;i++) b[i]=a[t++];    }else    {        for(int i=k;i<=high;i++) b[i]=a[s++];    }    for(int i=low;i<=high;i++) a[i]=b[i];}void mergesort(int low,int high){    if(low<high)    {        int mid=(low+high)/2;        mergesort(low,mid);        mergesort(mid+1,high);        Merge(low,mid,high);    }}int binarysearch(){    /*sort(a+1,a+n+1,greater<int>());//降序    int L=1,R=n,M;    while(L<=R)    {        M=(L+R)/2;        if(key==a[M]) return M;        else if(key<a[M]) L=M+1;        else R=M-1;    }*/    int key;    cout<<"请输入查找的数字：";    cin>>key;    int L=1,R=n,M;    while(L<=R)    {        M=(L+R)/2;        if(key==a[M]) return M;        else if(key<a[M]) R=M-1;        else L=M+1;    }    return -1;}int main(){    //freopen("in.txt","r",stdin);    //freopen("out.txt","w",stdout);    bool flag=true;    cout<<"************欢迎进入分治法实验界面***********"<<endl;    cout<<endl;    while(true)    {        switch(menu())        {        case 1:            {                gen();                print();                break;            }        case 2:            {                quicksort(1,n);                print();                break;            }        case 3:            {                mergesort(1,n);                print();                break;            }        case 4:            {                sort(a+1,a+n+1);//升序                print();                while(true)                {                    int ans=binarysearch();                    cout<<"查找数字的位置： "<<ans<<endl;                    cout<<"是否继续查找另外一个数字(Y/N):";                    char ch;                    cin>>ch;                    if(ch=='N') break;                }                break;            }        case 5:            {                print();                break;            }        case 6:            {                flag=false;                break;            }        default:            break;        }        if(!flag) break;    }    return 0;}
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