题解：CF2070C Limited Repainting

#include<bits/stdc++.h>
using namespace std;
#define int long long
int t,n,k,a[300005];
string s;
bool check(int x){//判断是否可行
	string s1="";
	for(int i=0;i<n;i++){
		if (a[i+1]<=x){
			s1+='3';
		}else if (s[i]=='R'){
			s1+='2';
		}else{
			s1+='1';
		}
	}
	int l=0,ans=0;
	while(l<n&&(s1[l]=='2'||s1[l]=='3')){
		l++;
	}
	for(;l<n;){
		while(l<n&&(s1[l]=='1'||s1[l]=='3')){
			l++;
		}
		while(l<n&&(s1[l]=='2'||s1[l]=='3')){
			l++;
		}
		ans++;
	}
	return ans<=k;
}
signed main(){
	cin>>t;
	while(t--){
		cin>>n>>k;
		cin>>s;
		for(int i=1;i<=n;i++){
			cin>>a[i];
		}
        //二分
		int l=0,r=1e9,res=0;
		while(l<=r){
			int mid=(l+r)/2;
			if (check(mid)){//如果可以
				res=mid;//记录答案
				r=mid-1;
			}else{
				l=mid+1;
			}
		}
		cout<<res<<endl;//输出
	}
	return 0;//表示完美结束
}