【基数排序】bzoj1901 Zju2112 Dynamic Rankings

论NOIP级别的n²算法…… 跟分块比起来，理论上十万的数据只慢4、5倍左右的样子……

 #include<cstdio>
 #include<algorithm>
 using namespace std;
 struct Point{int v,p;}t[];
 bool operator < (const Point &a,const Point &b){return a.v<b.v;}
 struct ASK{char op[];int x,y,k;}Ask[];
 int n,m,a[],en,ma[],en2,b[];
 int main()
 {
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;++i)
       {
           scanf("%d",&t[i].v);
           t[i].p=i;
       } en=n;
     for(int i=;i<=m;++i)
       {
           scanf("%s%d%d",Ask[i].op,&Ask[i].x,&Ask[i].y);
           if(Ask[i].op[]=='Q') scanf("%d",&Ask[i].k);
           else
             {
                 t[++en].v=Ask[i].y;
                 t[en].p=en;
             }
       } sort(t+,t+en+);
     ma[a[t[].p]=++en2]=t[].v;
     for(int i=;i<=en;++i)
       {
           if(t[i].v!=t[i-].v) en2++;
           ma[a[t[i].p]=en2]=t[i].v;
       } en=n;
     for(int i=;i<=m;++i)
       {
           if(Ask[i].op[]=='Q')
             {
                 int cnt=;
                 for(int j=Ask[i].x;j<=Ask[i].y;++j) ++b[a[j]];
                 for(int j=;;++j)
               {
                   if(b[j]) cnt+=b[j];
                   if(cnt>=Ask[i].k)
                   {
                       printf("%d\n",ma[j]);
                       for(int k=Ask[i].x;k<=Ask[i].y;k++) --b[a[k]];
                       goto OUT;
                   }
               }
             }
           else a[Ask[i].x]=a[++en];
           OUT:;
       }
     return ;
 }