codeforcesRound378C-dfs+树状数组

分成K个块，每个块内部dfs解决，然后用树状数组统计第i个元素前面有多少怪物已经消失，来计算当前的下标

 #include<bits/stdc++.h>

 #define inf 0x3f3f3f3f

 const int maxn=;

 using namespace std;

 typedef pair<int,char> P;

 vector<P> G[maxn+];

 int n;

 int k;

 int a[maxn+];

 int b[maxn+];

 int c[maxn+];

 int d[maxn+];

 int si[maxn+];

 int lowbit(int x){
     return x&(-x);
 }

 void add(int x,int val){
        while(x<=n){
         d[x]+=val;
         x+=lowbit(x);
        }
 }

 int sum(int x){
    int res=;
   while(x){
         res+=d[x];
         x-=lowbit(x);
   }
   return res;
 }

 int flag;

 int solve(int x,int y,int s){
     // printf("%d\n",s);
      if(s==b[x]){
         return ;
      }
      //printf("%d %d\n",y,s);
      for(int i=y+;i<=c[x];i++){
         if(a[i]==inf) continue;
         if(a[i]!=a[y]){
                 //printf("%d %d\n",i,y);
                 if(a[y]>a[i]){
                // printf("%d %d\n",y,i);
                 int temp=a[i];
                 int temp1=a[y];
                 a[i]+=a[y];
                 a[y]=inf;
                 add(y,);
                 //printf("%d %d %d\n",y,y-sum(y)+1,sum(y));
                 G[x].push_back(P(y-sum(y)+,'R'));
                 //printf("%d %d %d %d\n",x,i,y,s+temp);
                 if(solve(x,i,s+temp)){
                        // printf("dsasd\n");
                         return ;
                 }  else {
                   a[i]=temp;
                   a[y]=temp1;
                   add(y,-);
                   G[x].erase(G[x].end()-);
                   return ;
                 }
                 }
                 else {
              //   printf("%d %d\n",i,y);
                 int temp=a[i];
                 int temp1=a[y];
                 a[y]+=a[i];
                 a[i]=inf;
                 add(i,);
                  G[x].push_back(P(i-sum(i)+,'L'));
                // printf("%d %d\n",y,s+temp);
                  if(solve(x,y,s+temp)){
                         return ;
                 }  else {
                   a[i]=temp;
                   a[y]=temp1;
                   add(i,-);
                   G[x].erase(G[x].end()-);
                   return ;
                 }
                 }

         } else break;
      }
      for(int i=y-;i>c[x-];i--){
          if(a[i]==inf) continue;
         // printf("%d %d\n",i,y);
          if(a[i]!=a[y]){
                 if(a[y]>a[i]){
                 int temp=a[i];
                 int temp1=a[y];
                 a[i]+=a[y];
                 a[y]=inf;
                 add(y,);
                 G[x].push_back(P(y-sum(y)+,'L'));
                 if(solve(x,i,s+temp)){
                         return ;
                 }  else {
                   a[i]=temp;
                   a[y]=temp1;
                   add(y,-);
                   G[x].erase(G[x].end()-);
                   return ;
                 }
                 }
                 else {
                 int temp=a[i];
                 int temp1=a[y];
                 a[y]+=a[i];
                 a[i]=inf;
                 add(i,);
                  G[x].push_back(P(i-sum(i)+,'R'));
                  if(solve(x,y,s+temp)){
                         return ;
                 }  else {
                  a[i]=temp;
                  a[y]=temp1;
                  add(i,-);
                  G[x].erase(G[x].end()-);
                   return ;
                 }
                 }

         } else break;
      }
      for(int i=c[x-]+;i<=c[x];i++){
         if(a[i]!=inf&&i!=y&&a[i]!=a[y]){
           //printf("%d %d\n",i,s);
           if(solve(x,i,a[i])) return ;
         }
       }
      return ;
 }

 int main()
 {
     scanf("%d",&n);
     for(int i=;i<=n;i++){
         scanf("%d",&a[i]);
     }
     scanf("%d",&k);
     for(int i=;i<=k;i++){
         scanf("%d",&b[i]);
     }
     int cnt=;
     int temp=;
     for(int i=;i<=n;i++){
         if(temp<b[cnt]){
                 temp+=a[i];
                 si[cnt]++;
         }
         if(temp==b[cnt]){
                 c[cnt]=i;
                 cnt++;
                 temp=;
         } else if(temp>b[cnt]) {
                flag=;
                break;
         }
     }
     if(flag||cnt!=k+){
         printf("NO\n");
     } else {
        for(int i=;i<=k;i++){
                 if(si[i]==) continue;
                 int f=;
            for(int j=c[i-]+;j<c[i];j++){
                 if(a[j]!=a[j+]){
                         if(solve(i,j,a[j])){
                                 f=;
                                 break;
                         } else {
                          f=;
                          break;
                         }
                 }
            }
            if(!f){
                 if(solve(i,c[i],a[c[i]])){
                         f=;
                 }
            }
            if(!f){
                 printf("NO\n");
                 return ;
            }
        }
        printf("YES\n");
        for(int i=;i<=k;i++){
          for(int j=;j<G[i].size();j++){
                 printf("%d %c\n",G[i][j].first,G[i][j].second);
          }
        }
     }
     return ;
 }