暑假刷题第23天--8/7

D-游游的k-好数组_牛客周赛 Round 6 (nowcoder.com)（关键--a[1]=a[k+1]）

#include<iostream>
#include<algorithm>
using namespace std;
const int N=100005;
int a[N]; 
typedef pair<int,int>PII;
PII b[N];
void solve(){
	int n,k,x;
	cin>>n>>k>>x;
	for(int i=1;i<=n;i++){
		cin>>a[i];
        b[i%k].first=0;
        b[i%k].second=0;
	}
	for(int i=1;i<=n;i++){
		b[i%k].first=max(a[i],b[i%k].first);
		b[i%k].second++;
	}
	for(int i=1;i<=n;i++){
		x-=b[i%k].first-a[i];
	}
	if(x<0){
		cout<<-1<<endl;
		return;
	}
	sort(b,b+k);
	int ma=-1;
	for(int i=k-1;i>=0;i--){
        if(b[i].second!=0&&ma==-1)ma=b[i].first;
		if(b[i].second<=x&&b[i].second>0){
			ma=max(ma,b[i].first+x/b[i].second);
		}
	}
	cout<<ma<<endl;
}
int main(){
	int t;
	cin>>t;
	while(t--){
		solve();
	}
} 

Problem - E2 - Codeforces

#include<iostream>
#include<algorithm>
#include<map>
#include<string>
#include<cstring>
using namespace std;
const int N=200005;
int a[N]; 
typedef pair<int,int>PII;
bool vis[N];
int cnt[27];
char s[N],t[N];
int n,k;
void dfs(int u){
	vis[u]=true;
	cnt[s[u]-'a']--;
	cnt[t[u]-'a']++;
	if(u-k>=1&&!vis[u-k])dfs(u-k);
	if(u-(k+1)>=1&&!vis[u-(k+1)])dfs(u-(k+1));
	if(u+k<=n&&!vis[u+k])dfs(u+k);
	if(u+k+1<=n&&!vis[u+k+1])dfs(u+k+1);
}
void solve(){
	
	cin>>n>>k;
	cin>> (s+1) >> (t+1) ;
	memset(vis,0,sizeof(vis));
	for(int i=1;i<=n;i++){
		if(!vis[i]){
			memset(cnt,0,sizeof(cnt));
			dfs(i);
			for(int i=0;i<26;i++){
				if(cnt[i]!=0){
					cout<<"NO"<<endl;
					return;
				}
			}
		}
	}
	cout<<"YES"<<endl;
}
int main(){
	int t;
	cin>>t;
	while(t--){
		solve();
	}
}