A

太简单了，写完就删了

B1

#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main()
{int t;cin >> t;while (t--){int ch[33];memset(ch, 0, sizeof(ch));string str;cin >> str;for (int i = 0; i < str.length(); i++){int u = str[i] - 'a';ch[u]++;}int cou = 0;int gan = 0;for (int i = 0; i < 26; i++){if (ch[i] >= 2) cou++;else if (ch[i]==1) gan++;}cou+=gan/2;cout<<cou<<endl;}
}

B2
贪心思想

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int>PII;
bool cmp(PII a,PII b)
{return a.second<b.second;
}
bool cmp1(PII a,PII b)
{return a.first<b.first;
}
signed main()
{int t;cin>>t;while (t--){int n,k,num;int a[200101];// fill(a,a+n+2,0);memset(a,0,sizeof(a));vector<PII>cun;cin>>n>>k;int cou = 0;for (int i=0;i<n;i++){cin>>num;a[num]++;if (a[num]<=k) cou++;cun.push_back({num,i});}sort(cun.begin(),cun.end(),cmp1);cou = cou/k*k;memset(a,0,sizeof(a));for (int i=0;i<n;i++){a[cun[i].first]++;if (a[cun[i].first]<=k&&cou!=0){cun[i].first = cou%k+1;cou--;}else {cun[i].first = 0;}}sort(cun.begin(),cun.end(),cmp);for (int i=0;i<n;i++){cout<<cun[i].first<<" ";}cout<<endl;}
}

C
记录每个单词中的每个字母对于其他字母多多少（负数代表缺）缺的要存起来，多的加起来。

#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main()
{int t;cin >> t;while (t--){int n;cin >> n;int cou[6], sum[6],ds[6];//sum是队伍数量，ds是多多少vector<int> cun[6];for (int i=0;i<5;i++){sum[i]=0;ds[i]=0;}for (int j = 0; j < n; j++){memset(cou, 0, sizeof(cou));string str;cin >> str;for (int i = 0; i < str.length(); ++i){int u = str[i] - 'a';cou[u]++;}for (int i=0;i<5;i++){if (cou[i]>str.length()/2){sum[i]++;ds[i]+=2*cou[i]-str.length();}else{cun[i].push_back(str.length()-2*cou[i]);}}}int HH = 0;for (int i=0;i<5;i++){sort(cun[i].begin(),cun[i].end());int k = sum[i];for (int j=0;j<cun[i].size();++j){ds[i]-=cun[i][j];if (ds[i]>0) {++k;}else break;}if (k>HH) HH = k;}cout << HH << endl;}
}

D1

#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> PII;
signed main()
{int t;cin>>t;while (t--){int n,m,k;cin>>n>>m>>k;if (n%2==1) n--,k-=m/2;if (m%2==1) m--;if (k<0||k>n*m/2||(n*m/2%2!=k%2)) cout<<"No"<<endl;else cout<<"Yes"<<endl;	 }
}