VP时间

A.

计数器

比较c[i]与c[i+1]

1.ac

B.

数学？

好贪

让（n-1）个人都拿g/2(向上取整)-1，这样每个人都拿不到

或者全部人都拿g/2(向上取整)-1,省的是g/2-1,综合一下还是ans

最后一个人拿完全部

1.wa2

2.wa2

3,.wa2

4.g得奇数偶数

或者直接变成(a+b-1/b)（向下取整）

1.g&1

g/2(向上取整)==g/2

2.!(g&1)

g/2(向上取整==g/2-1

4.ac

C.

没时间

题解

A.

// Problem: A. Destroyer
// Contest: Codeforces - Codeforces Round 880 (Div. 2)
// URL: https://codeforces.com/contest/1836/problem/A
// Memory Limit: 256 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)#include<bits/stdc++.h>
#define eps 1e-5
#define INF 1e9
using namespace std;
typedef long long ll;
const int N = 2e6 + 9;
int a[N],c[N];
void Lan(){int n;cin>>n;memset(c,0,sizeof(c));for(int i=1;i<=n;i++){cin>>a[i];c[a[i]]++;}bool ok=true;for(int i=0;i<=100;i++){if(c[i+1]>c[i]){ok=false;}}if(!ok){cout<<"NO"<<'\n';}else{cout<<"YES"<<'\n';}}
int main() {ios::sync_with_stdio(false);cin.tie(0),cout.tie(0);int q;cin>>q;while (q--) {Lan();}return 0;
}

B.

1.

// Problem: B. Astrophysicists
// Contest: Codeforces - Codeforces Round 880 (Div. 2)
// URL: https://codeforces.com/contest/1836/problem/B
// Memory Limit: 256 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)#include<bits/stdc++.h>
#define eps 1e-5
#define INF 1e9
using namespace std;
typedef long long ll;
void Lan(){ll n,k,g;cin>>n>>k>>g;ll sum=min(k*g,(g-1)/2*n);ll res=(k*g-sum)%g;if(res>0){sum-=(g-1)/2;ll ans=((g-1)/2+res)%g;if(ans*2<g){sum+=ans;}else{sum-=g-ans;}}cout<<sum<<'\n';}
int main() {ios::sync_with_stdio(false);cin.tie(0),cout.tie(0);int q;cin>>q;while (q--) {Lan();}return 0;
}

2.

// Problem: B. Astrophysicists
// Contest: Codeforces - Codeforces Round 880 (Div. 2)
// URL: https://codeforces.com/contest/1836/problem/B
// Memory Limit: 256 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)#include<bits/stdc++.h>
#define eps 1e-5
#define INF 1e9
using namespace std;
typedef long long ll;
void Lan(){ll n,k,g;cin>>n>>k>>g;ll ans=0;if(g&1){ans=(g/2)*n;}else{ans=(g/2-1)*n;}ans/=g;if(ans>k){ans=k;}cout<<ans*g<<'\n';
}
int main() {ios::sync_with_stdio(false);cin.tie(0),cout.tie(0);int q;cin>>q;while (q--) {Lan();}return 0;
}

C.

题意原来是找按字典树找第k个满足等式的

枚举a就好了

// Problem: C. k-th equality
// Contest: Codeforces - Codeforces Round 880 (Div. 2)
// URL: https://codeforces.com/contest/1836/problem/C
// Memory Limit: 256 MB
// Time Limit: 1000 ms
// 
// Powered by CP Editor (https://cpeditor.org)#include<bits/stdc++.h>
#define eps 1e-5
#define INF 1e9
using namespace std;
typedef long long ll;
const int N = 2e6 + 9;
int t[10]={1,10,100,1000,10000,100000,1000000};
void Lan(){int a,b,c;ll k;cin>>a>>b>>c>>k;bool ok=false;for(int i=t[a-1];i<t[a];i++){int l=t[b-1],r=t[b]-1;l=max(l,t[c-1]-i);r=min(r,t[c]-1-i);if(r<l){continue;}if(k>r-l+1){k-=r-l+1;continue;}cout<<i<<" "<<"+"<<" "<<l+k-1<<" "<<"="<<" "<<i+(l+k-1)<<'\n';ok=true;break;}if(!ok){cout<<-1<<'\n';}
}int main() {ios::sync_with_stdio(false);cin.tie(0),cout.tie(0);int q;cin>>q;while (q--) {Lan();}return 0;
}