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| #include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define maxn 300005
#define put() putchar('\n')
#define Tp template<typename Ty>
#define Ts template<typename Ty,typename... Ar>
using namespace std;
void read(int &x){
int f=1;x=0;char c=getchar();
while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}
while (c>='0'&&c<='9') {x=x*10+c-'0';c=getchar();}
x*=f;
}
namespace Debug{
Tp void _debug(char* f,Ty t){cerr<<f<<'='<<t<<endl;}
Ts void _debug(char* f,Ty x,Ar... y){while(*f!=',') cerr<<*f++;cerr<<'='<<x<<",";_debug(f+1,y...);}
Tp ostream& operator<<(ostream& os,vector<Ty>& V){os<<"[";for(auto& vv:V) os<<vv<<",";os<<"]";return os;}
#define gdb(...) _debug((char*)#__VA_ARGS__,__VA_ARGS__)
}using namespace Debug;
#define fi first
#define se second
#define mk make_pair
const int mod=1e9+7;
int power(int x,int y=mod-2) {
int sum=1;
while (y) {
if (y&1) sum=sum*x%mod;
x=x*x%mod;y>>=1;
}
return sum;
}
int n,a[maxn];
int g[maxn][21],lg[maxn],f[maxn],ans[maxn];
pair<int,int>pre[maxn];
int query(int x,int y) {
if (x>y) return 0;
int z=lg[y-x+1];
return max(g[x][z],g[y-(1<<z)+1][z]);
}
void solve(void) {
int i,j;
read(n);
for (i=1;i<=n;i++) read(a[i]),f[i]=0,g[i][0]=i+a[i];
for (j=1;j<=19;j++) {
for (i=1;i+(1<<j)-1<=n;i++)
g[i][j]=max(g[i][j-1],g[i+(1<<j-1)][j-1]);
}
for (i=1;i<=n;i++) {
f[i]=f[i-1];
if (f[i-1]>=i) f[i]=max(f[i],i+a[i]),pre[i].fi=i-1,pre[i].se=1;
int l=-1,r=i,mid;
while (l+1<r) {
mid=l+r>>1;
if (f[mid]>=i-a[i]-1) r=mid;
else l=mid;
}
l++;
if (f[l]>=i-a[i]-1) {
int tmp=max(max(f[l],i-1),query(l+1,i-1));
if (f[i]<tmp) f[i]=tmp,pre[i].fi=l,pre[i].se=0;
}
}
int fl=0;
for (i=1;i<=n;i++) if (f[i]>=n) fl=1;
puts(fl?"YES":"NO");
if (fl) {
int i=n;
while (i) {
ans[i]=pre[i].se;
for (j=pre[i].fi+1;j<i;j++) ans[j]=1;
i=pre[i].fi;
}
for (j=1;j<=n;j++) putchar(ans[j]?'R':'L');
put();
}
}
signed main(void){
int T,i;
const int base=3e5;
for (i=2;i<=base;i++) lg[i]=lg[i/2]+1;
read(T);
while (T--) solve();
return 0;
}
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