AtCoder Beginner Contest 070

题目链接

http://abc070.contest.atcoder.jp/assignments

abc都是水题

A:

#include <bits/stdc++.h>
using namespace std;
int main(){
  int n;
  scanf("%d",&n);
  int a=n%10;
  int b=n/100;
  if(a==b)
    cout<<"Yes"<<endl;
  else
    cout<<"No"<<endl;
  return 0;
}

B:

#include <bits/stdc++.h>
using namespace std;
int main(){
  int x,y,a,b;
  scanf("%d%d%d%d",&x,&y,&a,&b);
  if(x<a){
    if(y>a)
      if(y<=b)
        cout<<y-a<<endl;
      else
        cout<<b-a<<endl;
    else
      cout<<0<<endl;
  }else if(x==a){
    cout<<min(y,b)<<endl;
  }else{
    if(b>x)
      if(b<=y)
        cout<<b-x<<endl;
      else
        cout<<y-x<<endl;
    else
      cout<<0<<endl;
  }
  return 0;
}

C:

#include <bits/stdc++.h>
#define ll long long int
#define N 105
using namespace std;
ll k[N];
ll gcd(ll a,ll b){
    return b?gcd(b,a%b):a;
}
int main(){
    int n;
    scanf("%d", &n);
    for(int i=1;i<=n;i++){
      scanf("%lld",&k[i]);
    }
    ll ans=k[1];
    for(int i=2;i<=n;i++){
      ans=ans/gcd(ans,k[i])*k[i];
    }
    printf("%lld
",ans);
    return 0;
}

D:

看这里