比赛详情

题目解答

A : [NOIP2002 普及组] 级数求和

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#include<iostream>
using namespace std;

int main(){
  int k = 0, n = 0;
  double sum = 0;
  scanf("%d", &k);
  while(sum <= k){
    sum += 1.0/++n;
  }
  printf("%d", n);
  return 0;
}

B : [NOIP1997 普及组] 棋盘问题

暴力枚举

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#include<iostream>
using namespace std;

int main(){
  int n = 0, m = 0;
  int ans1 = 0, ans2 = 0;
  scanf("%d%d", &n, &m);
  for(int i = 1; i <= n; i++){
    for(int j = 1; j <= m; j++){
      for(int k = i; k <= n; k++){
        for(int p = j; p <= m; p++){
          if(k-i == p-j){
            ans1++;
          }
          else{
            ans2++;
          }
        }
      }
    }
  }
  printf("%d %d", ans1, ans2);
  return 0;
}

公式求解

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#include<stdio.h>
using namespace std;
int main()
{
  int n,m;
  scanf("%d%d",&n,&m);
  int sum2=((m+1)*(n+1)*m*n)/4;
  int sum1=0;
  for(;n>=1&&m>=1;n--,m--)
  {
    sum1+=m*n;
  }
  printf("%d %d\n",sum1,sum2-sum1);
  return 0;
}

C : [NOIP2011 普及组] 数字反转

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#include<iostream>
using namespace std;

int main(){
  string str;
  cin >> str;
  if(str == "0"){
    printf("0");
    return 0;
  }
  int len = str.length();
  while(str[--len] == '0');
  if(str[0] == '-'){
    printf("-");
    for(int i = len; i > 0; i--){
      printf("%c", str[i]);
    }
  }
  else{
    for(int i = len; i >= 0; i--){
      printf("%c", str[i]);
    }
  }
  return 0;
}

D : [NOIP2016 普及组] 买铅笔

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#include<iostream>
using namespace std;

const int MAX_INT = 2e10;

int main(){
  int n = 0, ans = MAX_INT;
  scanf("%d", &n);
  for(int i = 0; i < 3; i++){
    int a = 0, b = 0, s = 0;
    scanf("%d%d", &a, &b);
    if(n % a == 0){
      s = n / a * b;
    }
    else{
      s = (n / a + 1) * b;
    }
    ans = min(ans, s);
  }
  printf("%d", ans);
  return 0;
}

E : 数字反转（升级版）

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#include<iostream>
using namespace std;
string s;
char p = 0;
int cnt = 0;
int main(){
    cin >> s;
    for(int i = 0; i < s.size(); i++){
        if(s[i] >= '0' && s[i] <= '9'){
          cnt++;
    }
    else{
            p = s[i];
            break;
        }
    }
    int x = cnt;
    cnt--;
    while(s[cnt] == '0' && cnt > 0){
    cnt--;
  } 
    for(int i = cnt; i >= 0; i--){
      cout << s[i];
  }
    if(p == 0){
      return 0;
    }
    cout << p;
    if(p == '%'){
    return 0;
  } 
    int m = s.size() - 1;
    while(s[x + 1] == '0' && x < m - 1){
      x++;
  }
    while(s[m] == '0' && m > x + 1){
      m--;
  }
    for(int i = m; i > x; i--){
      cout << s[i];
  }
    return 0; 
}