3.example

Example 5.0

输入50个学生的某门课程的成绩，打印出低于平均分的学生序号与成绩。

[+]

#include <iostream>
using namespace std;

int n;
double a[60],tot,avg;

int main(){
cin >> n;
for(int i=1;i<=n;i++){
  cin >> a[i];
  tot = tot + a[i];
}
avg = tot / n;
for(int i=1;i<=n;i++)
  if(a[i]<avg)
    cout << i << "," << a[i] << endl;
return 0;
}

Example 5.1

输入n个数，要求程序按输入时的逆序把这n个数打印出来，已知整数不超过100个。也就是说，按输入相反顺序打印这n个数。

[+]

#include <iostream>
using namespace std;

int a[100],n,x;

int main(){
  while(scanf("%d",&x)==1)
    a[n++] = x;
  for(int i=n-1;i>=1;i--)
    printf("%d ",a[i]);
  printf("%d",a[0]);
  return 0;
}

Example 5.2

将a数组中第一个元素移到数组末尾，其余数据依此往前平移一个位置。

[+]

#include <iostream>
#include <iomanip>
using namespace std;

int a[100],n;

int main(){
  cin >> n;

  for(int i=0;i<n;i++)
    cin >> a[i];
  int temp = a[0];
  for(int i=0;i<n-1;i++)
    a[i] = a[i+1];
  a[n-1]=temp;
  for(int i=0;i<n;i++)
    cout << setw(3) << a[i];
  cout << endl; 

  return 0;
}

Example 5.3

宾馆里有100个房间，从1-100编了号。第一个服务员把所有的房间门都打开了，第二个服务员把所有是2的倍数的房间做“相反处理”，第三个服务员把所有编号是3的倍数的房间做“相反处理”，...以后每个服务员都是如此。当第100个服务员来过之后，哪几扇门是打开的？（所谓“相反处理”是：原来开着的门关上，原来关上的门打开）。

[+]

#include <iostream>
using namespace std;

int a[110],n,first=1;

int main(){
  for(int i=1;i<=100;i++)
    for(int j=1;j<=100;j++)
      if(j%i==0)
        a[j]=!a[j];
  for(int i=1;i<=100;i++)
    if(a[i]){
      if(first)
        first=0;
      else
        cout << " ";
      cout << i;
    }
  cout << endl;

  return 0;
}

Example 5.4

约瑟夫问题：N个人围成一圈，从第一个开始报数，数到M的人出圈；再由下一个人开始报数，数到M的人出圈；...输出依次出圈的人的编号。N,M由键盘输入。

[+]

#include <iostream>
using namespace std;

bool a[101];
int n,m;

int main(){
  cin >> n >> m;
  for(int i=1;i<=n;i++)
    a[i] = false;
  int f=0,t=0,s=0;
  do{
    t++;
    if(t==n+1)
      t=1;
    if(a[t]==false)
      s++;
    if(s==m){
      s=0;
      cout << t << " ";
      a[t]=true;
      f++;
    }
  }while(f!=n);	

  return 0;
}

Example 5.5

输入n个整数，存放在数组a[1]至a[n]中，输出最大数所在位置(n<=10000)。
输入样例：

5
67 43 90 78 32

输出样例：

[+]

#include <iostream>
using namespace std;

int a[10001],n,k,maxa;

int main(){
  cin >> n;
  for(int i=1;i<=n;i++)
    cin >> a[i];
  maxa=a[1];
  k=1;
  for(int i=2;i<=n;i++){
    if(a[i]>maxa){
      maxa=a[i];
      k=i;
    }
  }
  cout << k << endl;
  
  return 0;
}

Example 5.6

编程输入十个正整数，然后自动按从大到小的顺序输出。（冒泡排序）
输入样例：

2 5 8 6 12 34 65 22 16 55

输出样例：

65 55 34 22 16 12 8 6 5 2

[+]

#include <iostream>
using namespace std;

const int n=10;
int a[n+1];

int main(){
  for(int i=1;i<=n;i++)
    cin >> a[i];
  for(int i=1;i<n;i++){
    for(int j=1;j<=n-i;j++){
      if(a[j]<a[j+1])
        swap(a[j],a[j+1]);
    }
  }	
  cout << a[1];
  for(int i=2;i<=n;i++)
    cout << " " << a[i];
  cout << endl;
  
  return 0;
}

Example 5.7

用筛选法求出100以内的全部质数，并按每行五个数显示。

[+]

#include <iostream>
#include <iomanip>
#include <cmath>
using namespace std;

const int n=100;
bool prime[n+1];

int main(){
  for(int i=0;i<=n;i++)
    prime[i]=true;
  for(int i=2;i<=sqrt(n);i++){
    if(prime[i])
      for(int j=2;j<=n/i;j++)
        prime[i*j]=false;
  }
  for(int i=2,t=0;i<=n;i++){
    if(prime[i]){
      cout << setw(5) << i;
      t++;
      if(t%5==0)
        cout << endl;
    }
  }
  return 0;
}

Exercise 1

与指定数字相同的数的个数，http://noi.openjudge.cn/ch0106/01/[+]

#include <iostream>
using namespace std;

int main()
{
  int N,m,a[100],sum=0;
  
  cin >> N;
  for(int i=0;i<N;i++)
  {
    cin >> a[i];	
  }
  cin >> m;
  for(int i=0;i<N;i++)
  {
    if (a[i]==m){
      sum = sum + 1;
    }
  }
  cout << sum << endl;
  
  return 0;	
}

陶陶摘苹果，http://noi.openjudge.cn/ch0106/02/[+]

#include <iostream>
using namespace std;

int main()
{
  int a[100],h,sum=0;
  
  for(int i=0;i<10;i++)
  {
    cin >> a[i];	
  }
  cin >> h;
  for(int i=0;i<10;i++)
  {
    if (a[i]<=30+h){
      sum = sum + 1;
    }
  }
  cout << sum << endl;
  
  return 0;	
}

计算书费，http://noi.openjudge.cn/ch0106/03/[+]

#include <iostream>
using namespace std;

int main()
{
  float cost=0, price[]={28.9,32.7,45.6,78.0,35.0,86.2,27.8,43.0,56.0,65.0};
  int num[10];
  
  for(int i=0;i<10;i++)
  {
    cin >> num[i];	
  }
  for(int i=0;i<10;i++)
  {
    cost = cost + price[i] * num[i]; 
  }
  printf("%.1f",cost);
  
  return 0;	
}

数组逆序重放，http://noi.openjudge.cn/ch0106/04/[+]

#include <iostream>
using namespace std;

int main()
{
  int num[100],n;
  
  cin >> n;
  for(int i=0;i<n;i++)
  {
    cin >> num[i];	
  }
  cout << num[n-1];
  for(int i=n-2;i>=0;i--)
  {
    cout << " " << num[i]; 
  }
  cout << endl;
  
  return 0;	
}

年龄与疾病，http://noi.openjudge.cn/ch0106/05/[+]

#include <iostream>
using namespace std;

int main()
{
  int num[100],n,sum=0;
  float age[4] = {0.0,0.0,0.0,0.0};
  
  cin >> n;
  for(int i=0;i<n;i++)
  {
    cin >> num[i];
    sum = sum + 1;
    if(num[i]<=18){
      age[0] = age[0] + 1;
    }else if(num[i]<=35){
      age[1] = age[1] + 1;
    }else if(num[i]<=60){
      age[2] = age[2] + 1;
    }else{
      age[3] = age[3] + 1;
    }
  }
  for(int i=0;i<4;i++)
  {
    printf("%.2f%%\n",age[i]*100.00f/sum); 
  }
  
  return 0;	
}

校门外的树，http://noi.openjudge.cn/ch0106/06/[+]

#include <iostream>
using namespace std;

int main()
{
  int begin[100],end[100],tree[10000],L,M,sum=0;
  
  cin >> L >> M;
  for(int i=0;i<=L;i++){
    tree[i] = 1;
  }
  for(int i=0;i<M;i++)
  {
    cin >> begin[i] >> end[i];
    for(int j=begin[i];j<=end[i];j++){
      tree[j]=0;
    }
  }
  for(int i=0;i<=L;i++)
  {
    if(tree[i]==1){
      sum = sum + 1;
    }; 
  }
  cout << sum << endl;
  
  return 0;	
}

有趣的跳跃，http://noi.openjudge.cn/ch0106/07/[+]

#include<iostream>
#include<cmath>
using namespace std;

int x[10000],y[10000];
int L,t,g,n,ok=1;

int main() {
  cin>>n;
  for(int i=1;i<=n;i++){
    cin>>x[i];	
  }
  for(int i=2;i<=n;i++){
    t=abs(x[i]-x[i-1]);	
    y[t]++;
  }	
  for(int i=1;i<n;i++){
    if(y[i]!=1){
      ok=0;
    }
  }
  if(ok)
    cout<<"Jolly";
  else 
    cout<<"Not jolly";
  return 0;
}

石头剪刀布，http://noi.openjudge.cn/ch0106/08/[+]

#include <iostream>
using namespace std;

int main(){
  int a[10000],b[10000];
  int n,na,nb;
  cin >> n >> na >> nb;
  
  for(int i=0;i<na;i++) cin >> a[i];
  for(int i=0;i<nb;i++) cin >> b[i];
  
  int p = na;
  while(p<n){
    a[p] = a[p%na];
    p++;
  }
  p = nb;
  while(p<n){
    b[p] = b[p%nb];
    p++;
  }

  int A=0,B=0;	
  for(int i=0;i<n;i++){
    if(a[i]==0 && b[i]==2){
      A++;
    }
    if(a[i]==2 && b[i]==5){
      A++;
    }
    if(a[i]==5 && b[i]==0){
      A++;
    }
    if(a[i]==2 && b[i]==0){
      B++;
    }
    if(a[i]==5 && b[i]==2){
      B++;
    }
    if(a[i]==0 && b[i]==5){
      B++;
    }
  }
  
  if(A>B)
    cout << "A" << endl;
  else if(B>A)
    cout << "B" << endl;
  else
    cout << "draw" << endl; 
  
  return 0;
}

向量点积计算，http://noi.openjudge.cn/ch0106/09/[+]

#include <iostream>
using namespace std;

int main()
{
  int n,a[1000],b,sum=0;
  
  cin >> n;
  for(int i=0;i<n;i++)
  {
    cin >> a[i];
  }
  for(int i=0;i<n;i++)
  {
    cin >> b;
    sum = sum + a[i] * b;
  }
  cout << sum << endl;
  
  return 0;	
}

大整数加法，http://noi.openjudge.cn/ch0106/10/[+]

#include <iostream>
#include <string.h>
using namespace std;

int main(){
  char a[300],b[300];
  cin >> a >> b ;
  //cout << a << b << endl;
  int alen = strlen(a);
  int blen = strlen(b);
  //cout << alen << blen << endl;
  
  int max = alen;
  if (blen>max) max = blen;
  //cout << max << endl;
  
  int c[max+1],d[max+1];
  int j,k;
  for (int i=1;i<=max;i++){
    if(i<=alen)
      c[max-i] = a[alen-i] - 48;
    else
      c[max-i] = 0;
      //cout << "a" << c[max-i] << endl;
    if(i<=blen)
      d[max-i] = b[blen-i] - 48;
    else
      d[max-i] = 0;
    //cout << "b" << d[max-i] << endl;
  }
  //printf("%d\n",max);
  
  int more = 0, p=0;
  //cout << more << endl;
  for (int i=max-1 ;i>=0;i--){
    //cout << more << " ";
    p = c[i] + d[i] + more;
    //cout << c[i] << "  " << d[i] <<  "  "  << p << " " << more << endl;
    if(p>=10){
      more = 1;
      c[i] = p - 10;
    }else{
      more = 0;
      c[i] = p ;
    }
  }
  
  int i = 0;
  if (more>0) cout << more;
  else
  for (i=0;i<max;i++) {
    //cout << c[i] << endl;
    if (c[i]>0){
      break;
    }
  } 
  if(i==max) cout << 0 << endl;
  
  for (int j=i;j<max;j++)
    cout << c[j];
  cout << endl;
      
  return 0;
}

大整数减法，http://noi.openjudge.cn/ch0106/11/[+]

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

int a[201],b[201];
char c[201];

int main(){
  gets(c);
  int lena = strlen(c);
  for(int i=0;i<lena;i++)
      a[i] = c[i] - '0';
  reverse(a,a+lena);
  
  gets(c);
  int lenb = strlen(c);
  for(int i=0;i<lenb;i++)
      b[i] = c[i] - '0';
  reverse(b,b+lenb);
  
  for(int i=0;i<lenb;i++){
    if(a[i]<b[i]){
        a[i] = a[i] + 10 - b[i];
      a[i+1] = a[i+1] -1; 
    }else{
      a[i] = a[i] - b[i];
    }
  }

  reverse(a,a+lena);
  int i=0;
  while(a[i]==0) i++;
  for(;i<lena;i++)
    cout << a[i];
  cout << endl;	
    
    return 0;
}

计算2的N次方，http://noi.openjudge.cn/ch0106/12/[+]

#include <iostream>
using namespace std;

int ans[100];

int main(){
  int n,i,m=1;
  cin >> n;
  ans[0]=1;
  while(n--){
    int more =0;
    i=0;
    for(;i<m;i++){
      int temp = ans[i] * 2 + more;
      ans[i]=temp % 10;
      more = temp / 10;
    }
    if(more){
          ans[i]=more;
      m++;
    }	
  }
  
  while(!ans[i]) i--;
  for(int t=i;t>=0;t--){
    cout << ans[t];
  }
  cout << endl;
  
    return 0;
}

大整数的因子，http://noi.openjudge.cn/ch0106/13/[+]

#include <iostream>
#include <cstring>
using namespace std;

int n[100];
char c[100];

int main(){
  int flag = 1;
  gets(c);

  int len = strlen(c);
  for(int i=0;i<len;i++) 
    n[i] = c[i]-'0';

  for(int k=2;k<=9;k++){
    int r = 0;
    for(int i=0;i<len;i++){
      r = (n[i] +r*10) % k; 
    }
    if(r==0){
      cout << k << " ";
      flag = 0;
    }
  }		
  if(flag) cout << "none" << endl;
  else cout << endl;
    
  return 0;
}

求10000以内n的阶乘，http://noi.openjudge.cn/ch0106/14/[+]

#include <iostream>
using namespace std;

int ans[100000];

int main(){
  int n,len=1;
  cin >> n;
  ans[0]=1;
  for(int i=2;i<=n;i++){
    int more=0,j=0;
        for(;j<len;j++){
          int tmp = ans[j]*i;
          int r =  (tmp + more) / 10;
          ans[j] = (tmp + more) % 10;
      more = r; 
    }
    while(more>0){
      ans[len++] = more % 10;
      more = more / 10;
    }
  }
  for(int i=len-1;i>=0;i--)
      cout << ans[i];
  cout << endl;
  
    return 0;
}

阶乘和，http://noi.openjudge.cn/ch0106/15/[+]

#include <iostream>
using namespace std;

int ans[100];
int p[100];

int main(){
  int n,len=1;
  cin >> n;
  p[0]=1,ans[0]=1;
  for(int i=2;i<=n;i++){
    int more=0;
        for(int j=0;j<len;j++){
          int tmp = p[j]*i;
          int r =  (tmp + more) / 10;
          p[j] = (tmp + more) % 10;
      more = r; 
    }
    while(more>0){
      p[len++] = more % 10;
      more = more / 10;
    }
    more = 0;
    for(int j=0;j<=len;j++){
      int tmp = ans[j]+p[j]+more; 
      ans[j] = tmp % 10;
      more = tmp / 10;
    }
  }
  for(int i=len-1;i>=0;i--)
      cout << ans[i];
  cout << endl;		
  
    return 0;
}

不高兴的津津，http://noi.openjudge.cn/ch0109/03/[+]

#include <iostream>
using namespace std;

int main(){
  int a,b,flag=1;
  
  for(int i=1;i<=7;i++){
    cin >> a >> b;
    if(a+b>8){
      flag = 0;
      cout << i << endl;
      break;
    }
  }
  
  if(flag){
    cout << 0 << endl;
  }
  return 0;
}

最大值和最小值的差，http://noi.openjudge.cn/ch0109/05/[+]

#include <iostream>
using namespace std;

int main(){
  int n,a,minn=100000,maxx=-100000;
  cin >> n;
  for(int i=1;i<=n;i++){
    cin >> a;
    maxx = max(maxx,a);
    minn = min(minn,a);
  }
  cout << maxx - minn <<endl;	
  return 0;
}

不与最大数相同的数字之和，http://noi.openjudge.cn/ch0109/07/[+]

#include <iostream>
using namespace std;

int main(){
  int n,a[101],sum=0,maxx=-10000000;
  
  cin >> n;
  
  for(int i=0;i<n;i++){
    cin >> a[i];
    maxx = max(maxx,a[i]);
  }
  
  for(int i=0;i<n;i++){
    if(a[i]!=maxx)
      sum = sum + a[i];
  }
  
  cout << sum << endl;
  
  return 0;
}

白细胞计数，http://noi.openjudge.cn/ch0109/08/[+]

#include <iostream>
#include <cmath>
using namespace std;

int main(){
  int n,mx,mn;
  double a[305],avg,sub,sum=0.0,maxx=0.0,minn=10000000000000.0;

  cin >> n;
  for(int i=0;i<n;i++){
    cin >> a[i];
    if(a[i]>maxx){
      maxx = a[i];
      mx = i;
    }
    if(a[i]<minn){
      minn = a[i];
      mn = i;
    }
    sum = sum + a[i];
  }
  avg = (sum-maxx-minn)/(n-2);

  maxx = 0.0;
  for(int i=0;i<n;i++){
    if(i!=mn && i!=mx){
      maxx = max(maxx,abs(avg-a[i]));
    }
  }
  printf("%.2f %.2f",avg,maxx);
  
  return 0;
}

直方图，http://noi.openjudge.cn/ch0109/09/[+]

#include <iostream>
using namespace std;

int n,a[10005],d[10005],fmax=0;
int main(){
  cin >> n;

  for(int i=0;i<n;i++){
    cin >> a[i];
    fmax = max(fmax,a[i]);
    d[a[i]]++;
  }

  for(int i=0;i<=fmax;i++)
    cout << d[i] << endl;
    
  return 0;
}

最长平台，http://noi.openjudge.cn/ch0109/12/[+]

#include <iostream>
using namespace std;

int main(){
  int n,a,tmp=-1,tim=0,max=1;
  cin >> n;
  for(int i=0;i<n;i++){
    scanf("%d",&a);
    if(a!=tmp){
      if(tim>max) max = tim;
      tim = 1;
      tmp = a;
    }else{
      tim = tim + 1;
    }
  } 
  
  if(tim>max) max = tim;
  
  cout << max << endl;
  
  return 0;
}

整数去重，http://noi.openjudge.cn/ch0109/13/[+]

#include <iostream>
using namespace std;
int f[200];
int main(){
  int n,a,first=1;
  cin >> n;
  for(int i=0;i<n;i++){
    scanf("%d",&a);
    if(!f[a]){
      if(first){
        cout << a;
        first = 0;
      }else{
        cout << " " << a;
      }
      f[a]=1;
    }
  }
  cout << endl;
  
  return 0;
}

铺地毯，http://noi.openjudge.cn/ch0109/14/[+]

#include <iostream>
using namespace std;

int n,dt[10005][4],x,y,idx=-1;
int main(){
  cin >> n;
  for(int i=0;i<n;i++){
    scanf("%d %d %d %d",&dt[i][0],&dt[i][1],&dt[i][2],&dt[i][3]);
  }
  cin >> x >> y;
  for(int i=0;i<n;i++){
    if(x-dt[i][0]>=0 && x-dt[i][0]<=dt[i][2] && y-dt[i][1]>=0 && y-dt[i][1]<=dt[i][3]){
      idx = i+1;
    }
  }	
  cout << idx << endl;
  
  return 0;
}