Codeforces Round #619 (Div. 2)

A.Three Strings

 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 7;
const int inf = 0x3f3f3f3f;
char a[110],b[110],c[110];
int t;
int main()
{
    scanf("%d",&t);
    while(t--)
    {
        scanf("%s%s%s",a,b,c);
        int len=strlen(a);
        bool ok=false;
        for(int i=0;i<len;i++)
        {
            if(a[i]==c[i]||b[i]==c[i]) continue;
            ok=true;
        }
        if(ok) puts("NO");
        else puts("YES");
    }
    return 0;
}

B. Motarack's Birthday

 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 7;
const int inf = 0x3f3f3f3f;
int a[N];
int t,n;
void work(int a[])
{
    bool ok=true;
    int maxx=0,minx=inf;
    int res=0;
    for(int i=1;i<=n;i++)
    {
        if(a[i]!=-1)
        {
            ok=false;
            if(a[i-1]!=-1) res=max(res,abs(a[i]-a[i-1]));
            if(a[i+1]!=-1) res=max(res,abs(a[i]-a[i+1]));
            continue;
        }
        if(a[i-1]!=-1) maxx=max(maxx,a[i-1]),minx=min(minx,a[i-1]);
        if(a[i+1]!=-1) maxx=max(maxx,a[i+1]),minx=min(minx,a[i+1]);
    }
    if(ok)
    {
        cout<<0<<" "<<1<<endl;
 
    }
    else
    {
        int k = (maxx+minx+1)/2;
        cout<<max(res,max(abs(maxx-k),abs(minx-k)))<<" "<<k<<'
';
    }
}
int main()
{
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        for(int i=1;i<=n;i++) scanf("%d",&a[i]);
        a[0]=-1, a[n+1]=-1;
        work(a);
    }
    return 0;
}

C. Ayoub's function

 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 7;
const int inf = 0x3f3f3f3f;
int T;
ll n,m;
void work(ll n, ll m)
{
    ll ans=(n+1)*n/2;
    ll d=n-m;
    ll x=d/(m+1);
    ll y=d%(m+1);
    ll cnt=m-y+1;
    ans-=cnt*(x*(x+1)/2);
    ans-=y*((x+2)*(x+1)/2);
    cout<<ans<<'
';
}
int main()
{
    scanf("%d",&T);
    while(T--)
    {
        cin>>n>>m;
        work(n,m);
    }
    return 0;
}