【真题】暑假备战CSP-J/S：CSP-J2021普及组初赛(第一轮)试题及参考答案电子版(PDF版、无水印可直接打印)

solve(n)   
    if n <=1 return 1     
    else if n>=5 return n*solve(n-2)   
    else return n*solve(n-1)

#include <stdio.h>
using namespace std;
int n;
int a[1000];
int f(int x)
{
    int ret = 0;
    for (; x; x &=x-1) ret++;
    return ret;
 }
 
 int g(int x)
 {
     return x & -x;
 }
 
 int main()
 {
     cin >> n;
     for (int i = 0; i < n; i++) cin >> a[i];
     for (int i = 0; i < n; i++)
         cout << f(a[i]) + g(a[i]) << '';
     cout << endl;
     return 0;
 }

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

char  base[64];  
char  table[256]; 

void init()
{
  for (int i = 0; i < 26; i++) base[i] = 'A' + i;
  for (int i = 0; i < 26; i++) base[26 + i] = 'a' +i;
  for (int i = 0; i < 10; i++) base[52 + i] = '0' +i;
  base[62] = '+' , base[63] = '/';
  
  for (int i = 0; i < 256; i++} table[i] = 0xff;
  for (int i = 0; i < 64; i++} table[base[i]] = i;
  table['='] = 0
}

string decode(string str)
{
    string ret;
    int i;
    for (i = 0; i < str.size(); i += 4) {
        ret += table[str[i]] << 2 | table[str[i + 1]] >> 4;
        if (str[i + 2] != '=')
            ret += (table[str[i + 1]] & 0x0f) << 4 | table[str[i + 2]] >> 2;
        if (str[i + 3] != '=')
            ret += table[str[i + 2]] << 6 | table[str[i + 3]];
    }
    return ret;
}

int main()
{
    init();
    cout << int(table[0]) << end1;
    
    string str;
    cin >> str;
    cout << decode(str) << end1;
    return 0;
} 

#include <iostream>
using namespace std;

const int n = 100000;
const int N = n + 1;

int m;
int a[N],b[N],c[N], d[N];
int f[N],g[N];

void init()
{
    f[1] = g[1] = 1;
    for (int i = 2; i <= n; i++){
        if (!a[i]) {
          b[m++] = i;
          c[i] = 1, f[i] = 2;
          d[i] = 1, g[i] = i+ 1;
        }
        for (int j = 0; j < m && b[j] * i <= n; j++){
          int k = b[j];
          a[i * k] = 1;
          if (i % k == 0){
            c[i * k] = c[i] + 1;
            f[i * k] = f[i] / c[i * k]*(c[i * k] + 1);
            d[i * k] = d[i];
            g[i * k] = g[i] * k + d[i];
            break;
          }
          else {
            c[i * k] = 1;
            f[i * k] = 2 * f[i];
            d[i * k] = g[i];
            g[i * k] = g[i] * (k + 1);
          }
        }
    }
}
int main() {
  init();

  int x;
  cin >> x;
  cout<<f[x]<<" "<<g[x]<<endl;
  return 0;
}

#include <iostream>
using namespace std;

const int MAXN = 1000000; 
int F[MAXN];

int main() {  
    int n;
    cin >> n;
    int i = 0,p =0,c= 0;
    while (①) {
        if (F[i] == 0) {
            if (②) {
                F[i] = 1;
               ③;
            }
            ④;
        }
           ⑤;
    }
    int ans = -1;
    for (i = 0; i < n; i++)
        if (F[i] == 0)
            ans = i;
    cout << ans << endl;
    return 0;
}

#include <iostream>
using namespace std;

struct point {
  int x, y, id;
};

bool equals(point a, point b){
  return a.x== b.x && a.y == b.y;
}

bool cmp (point a,point b){
  return a.x!=b.x?a.x<b.x:a.y<b.y; 
}

void sort(point A[], int n){
  for (int i = 0; i < n; i++)
       for (int j = 1;j < n; j++)
          if (cmp(A[j],A[j-1])) {
            point t = A[j];
            A[j] =A[j-1];
            A[j -1] =t;
          }
}

int unique (point A[],int n){
  int t= 0;
  for(int i= 0; i < n; i++)
      if(②)
         A[t++]=A[i];
     return t;
}

bool binary_search(point A[], int n, int x ,int y){
  point p;
  p.x = x;
  p.y = y;
  p.id = n;
  int a =0, b = n-1;
    while (a < b){
      int mid = ③;
      if (④)
         a = mid + 1;
         else
         b = mid;
    }
    return equals(A[a] , p);
}

const int MAXN = 1000;
point A [MAXN];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++){
    cin >> A[i].x >> A[i].y;
    A[i].id = i;
  }
  sort(A,n);
  n = unique(A , n);
  int ans = 0;
  for(int i = 0; i < n; i++)
     for (int j = 0; j < n; j++)
     if(⑤ && binary_search (A, n, A[i].x,A[j].y) &&
              binary_search(A, n, A[j].x, A[i].y)){
            ans++;
          }
        cout << ans << endl;    
  return 0;
}