Codeforces Round 923 (Div. 3)(A~F)

目录

• A
• B
• C
• D
• E
• F

A

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;

void solve()
{
	int n;cin>>n;
	string s;cin>>s;
	int x=0,y=0;
	rep(i,0,s.size()-1){
		if(s[i]=='B')	y=i;
	}
	fep(i,s.size()-1,0){
		if(s[i]=='B')	x=i;
	}
	cout<<y-x+1<<endl;
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}

B

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;

void solve()
{
	int n;
	cin>>n;
	vector<int>a(n+1);
	rep(i,1,n)	cin>>a[i];
	map<int,set<char>>kk;
	for(char i='a';i<='z';++i){
		kk[0].insert(i);
	}
	string ans;
	rep(i,1,n){
		int cnt=a[i];
		char c=*kk[cnt].begin();
		kk[cnt].erase(c);
		kk[cnt+1].insert(c);
		ans+=c;
	}
	cout<<ans<<endl;
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}

C

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;

void solve()
{
	int n,m,k;
	cin>>n>>m>>k;
	vector<int>a(n+1),b(m+1);
	set<int>s1,s2;
	rep(i,1,n){
		cin>>a[i];
		s1.insert(a[i]);
	}
	rep(i,1,m){
		cin>>b[i];
		s2.insert(b[i]);
	}
	
	if(s1.size()<k/2||s2.size()<k/2){
		cout<<"No"<<endl;
		return;
	}
	int cnta=0,cntb=0,cntss=0;
	rep(i,1,k){
		if(s1.count(i)&&s2.count(i)){
			cntss++;
		}else if(s1.count(i)&&!s2.count(i)){
			cnta++;
		}else if(!s1.count(i)&&s2.count(i)){
			cntb++;
		}else{
			cout<<"No"<<endl;
			return;
		}
	}
	if(cnta<k/2){
		cntss-=(k/2-cnta);
	}
	if(cntb<k/2){
		cntss-=(k/2-cntb);
	}
	if(cntss<0){
		cout<<"No"<<endl;
	}else{
		cout<<"Yes"<<endl;
	}
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}

D

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
//#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;
const int N=1e6+10;

#include <iostream>
using namespace std;


void solve()
{
	int n;cin>>n;
	vector<int>a(n+1),lmin(n+1),lmax(n+1);
	rep(i,1,n){
		cin>>a[i];
		lmin[i]=lmax[i]=0;
	}
	stack<int>stk;
	rep(i,1,n){
		while(stk.size()&&a[i]<=a[stk.top()])	stk.pop();
		if(stk.size()){
			lmin[i]=stk.top();
		}	
		stk.push(i);
	}
	while(stk.size())	stk.pop();
	rep(i,1,n){
		while(stk.size()&&a[i]>=a[stk.top()])	stk.pop();
		if(stk.size()){
			lmax[i]=stk.top();
		}	
		stk.push(i);
	}
//	rep(i,1,n)	cout<<lmin[i]<<' ';
//	cout<<endl;
//	rep(i,1,n)	cout<<lmax[i]<<' ';
//	cout<<endl;
	int q;cin>>q;
	while(q--){
		int l,r;cin>>l>>r;
		int minn=lmin[r],maxx=lmax[r];
		if(minn>=l){
			cout<<minn<<' '<<r<<endl;
		}else if(maxx>=l){
			cout<<maxx<<' '<<r<<endl;
		}else{
			cout<<"-1 -1"<<endl;
		}
	}
	cout<<endl;
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}

E

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;
const int N=1e6+10;

#include <iostream>
using namespace std;


void solve()
{
	int n,k;cin>>n>>k;
	vector<int>ans(n+1);
	int bb=1,dd=n;
	rep(i,1,k){
		if(i&1){
			//从大到小去放
			for(int j=i;j<=n;j+=k){
				ans[j]=dd--;
			}
		}else{
			//从小到大去放
			for(int j=i;j<=n;j+=k){
				ans[j]=bb++;
			}
		}
	}
	rep(i,1,ans.size()-1)	cout<<ans[i]<<' ';
	cout<<endl;
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}

F

#include <bits/stdc++.h> 
#define int long long
#define rep(i,a,b) for(int i = (a); i <= (b); ++i)
#define fep(i,a,b) for(int i = (a); i >= (b); --i)
#define pii pair<int, int>
#define pll pair<long long, long long>
#define ll long long
#define db double
#define endl '\n'
#define x first
#define y second
#define pb push_back

using namespace std;

const int N=2e5+10;
int fa[N];
struct edge{
	int x,y,w;
}e[N];
vector<int>g[N];

int find(int x){
	if(x==fa[x])	return x;
	return fa[x]=find(fa[x]);
}
int n,m;

vector<int>path;
int vis[N];
void dfs(int u,int tag){
	vis[u]=1;
	path.pb(u);
	if(u==tag){
		cout<<path.size()<<endl;
		for(auto i:path)	cout<<i<<' ';
		cout<<endl;
	}else{
		for(auto y:g[u]){
			if(vis[y])	continue;
			dfs(y,tag);
		}
	}
	path.pop_back();
}

void solve()
{
	cin>>n>>m;
	rep(i,1,n)	fa[i]=i;
	rep(i,1,n)	vis[i]=0;
	path.clear();
	rep(i,1,n)	if(g[i].size())	g[i].clear();
	rep(i,1,m){
		int u,v,w;cin>>u>>v>>w;
		e[i]={u,v,w};
	}
	sort(e+1,e+1+m,[&](edge t1,edge t2){return t1.w>t2.w;});
	
	int id=0,ans=1e9;
	rep(i,1,m){
		int u=find(e[i].x),v=find(e[i].y);
		if(u==v){
			id=i;
			ans=min(ans,e[i].w);
		}else{
			fa[u]=v;
		}		
	}
	cout<<ans<<' ';
	rep(i,1,m){
		if(id==i)	continue;
		int x=e[i].x,y=e[i].y;
		g[x].pb(y);g[y].pb(x);
	}
	dfs(e[id].x,e[id].y);
}

signed main(){
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
//   	freopen("1.in", "r", stdin);
  	int _;
	cin>>_;
	while(_--)
	solve();
	return 0;
}