比赛总结——atcoder beginner contest 109

Posted 2021-01-05 dreagonm

第一次AK的ABC

虽然题非常简单

但是值得纪念一下

T1

一道很水的题

不存在做法

纯粹乱跑

但是我把Yes打成YES了，哭唧唧

#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  int a,b;
  scanf("%d %d",&a,&b);
  if((1*a*b)%2==1||(2*a*b)%2==1||(3*a*b)%2==1)
    printf("Yes
");
  else
    printf("No
");
  return 0;
}

T2

就是普通的判重和模拟

stl真好用

#include <cstdio>
#include <algorithm>
#include <cstring>
#include <string>
#include <set>
#include <iostream>
using namespace std;
int n;
set<string> s;
string a;
char lat;
int main(){
  scanf("%d",&n);
  for(int i=1;i<=n;i++){
    cin>>a;
    if(s.count(a)){
      printf("No
");
      return 0;
    }
    if(i>1&&a[0]!=lat){
      printf("No
");
      return 0;
    }
    lat=a[a.length()-1];
    s.insert(a);
  }
  printf("Yes
");
  return 0;
}

T3

有趣的GCD应用

秒掉

#include <cstdio>
#include <cstring>
#include <algorithm>
#define int long long
using namespace std;
int n,x,pos[110000];
int gcd(int a,int b){
  return (b==0)?a:gcd(b,a%b);
}
signed main(){
  scanf("%lld %lld",&n,&x);
  for(int i=1;i<=n;i++)
    scanf("%lld",&pos[i]);
  for(int i=1;i<=n;i++)
    pos[i]-=x;
  ++n;
  pos[n]=0;
  sort(pos+1,pos+n+1);
  int ans=pos[2]-pos[1];
  for(int i=2;i<=n-1;i++){
    ans=gcd(ans,pos[i+1]-pos[i]);
  }
  printf("%lld",ans);
  return 0;
}

T4

乍一看不好做其实很水的构造

#include <cstdio>
#include <algorithm>
#include <cstring>
#define int long long
using namespace std;
int mat[510][510],mat2[510][510],ans=0;
int h,w;
signed main(){
  scanf("%lld %lld",&h,&w);
  for(int i=1;i<=h;i++)
    for(int j=1;j<=w;j++)
      scanf("%lld",&mat[i][j]),mat2[i][j]=mat[i][j];
  for(int i=1;i<=h;i++)
    for(int j=1;j<=w-1;j++){
      if(mat2[i][j]%2==0)
        continue;
      else{
        ans++;
        mat2[i][j+1]++;
        mat2[i][j]--;
      }
      //ans+=mat2[i][j],mat2[i][j+1]+=mat2[i][j],mat2[i][j]=0;
    }
  for(int i=1;i<=h-1;i++){
    //ans+=mat2[i][w],mat2[i+1][w]+=mat2[i][w],mat2[i][w]=0;
    if(mat2[i][w]%2==0)
      continue;
    else{
      ans++;
      mat2[i+1][w]++;
      mat2[i][w]--;
    }
  }
  printf("%lld
",ans);
  for(int j=1;j<=h;j++)
    for(int i=1;i<=w-1;i++){
      if(mat[j][i]%2==0)
        continue;
      else{
        printf("%lld %lld %lld %lld
",j,i,j,i+1);
        mat[j][i+1]++;
        mat[j][i]--;
      }
//      for(int k=1;k<=mat[j][i];k++){
//        printf("%d %d %d %d
",j,i,j,i+1);
//        mat[j][i+1]+=1;
//      }
//      mat[j][i]=0;
  }
  for(int i=1;i<=h-1;i++){
    if(mat[i][w]%2==0)
      continue;
    else{
      mat[i+1][w]++;
      mat[i][w]--;
      printf("%lld %lld %lld %lld
",i,w,i+1,w);
    }
  }
//    for(int k=1;k<=mat[i][w];k++)
//      printf("%d %d %d %d
",i,w,i+1,w),mat[i+1][w]++;
  return 0;
}