【LibreOJ10121】与众不同（RMQ，二分）

题意：

思路：

C++

 #include<map>
 #include<set>
 #include<cmath>
 #include<cstdio>
 #include<vector>
 #include<cstring>
 #include<cstdlib>
 #include<iostream>
 #include<algorithm>
 #define M 1000000
 #define MAXN 210000
 using namespace std;

 int g[MAXN][];
 int last[M*];
 int a[MAXN],st[MAXN],f[MAXN];

 int ask(int x,int y)
 {
   if(x>y) return ;
   int len=y-x+; int l=log(len)/log();
   return max(g[x][l],g[y-(<<l)+][l]);
 }

 int main()
 {
     freopen("data.in","r",stdin);
     freopen("1.out","w",stdout);
     int n,m,x,y;
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++)
     {
         scanf("%d",&a[i]);
         a[i]+=M;
         st[i]=max(st[i-],last[a[i]]+);
         last[a[i]]=i;
         g[i][]=f[i]=i-st[i]+;
     }
     int l=log(n)/log();
     for(int i=;i<=l;i++)
      for(int j=;j+(<<(i-))<=n;j++)
       g[j][i]=max(g[j][i-],g[j+(<<(i-))][i-]);
     for(int i=;i<=m;i++)
     {
         scanf("%d%d",&x,&y);
         x++; y++;
         int l=x; int r=y;
         int tmp=x;
         while(l<=r)
         {
             int mid=(l+r)/;
             if(st[mid]<x) {tmp=mid;l=mid+;}
              else r=mid-;
         }
         int ans=max(tmp-x+,ask(tmp+,y));
         printf("%d\n",ans);
     }
     return ;
 }
  

pascal

 const maxn=;
       max=;
 var n,m,i,x,y,t,j,ans,keypoint,l,r:longint;
     a,opt,pre:array[..maxn]of longint;
     rmq:array[..maxn,..]of longint;
     f:array[-max..max]of longint;
     ch:char;
 function find(x,y:longint):longint;
   var left,right,mid:longint;
   begin
     left:=x;right:=y;
     while left<=right do begin
       mid:=(left+right)shr ;
       if pre[mid]<=y then left:=mid+
       else right:=mid-;
     end;
     find:=left;
   end;
 function findmax(x,y:longint):longint;
   var i,j:longint;
   begin
     i:=;j:=;
     while *j<=y-x+ do begin
       inc(i);
       j:=j*;
     end;
     if rmq[x,i]>rmq[y+-j,i] then findmax:=rmq[x,i]
     else findmax:=rmq[y+-j,i];
   end;
 begin
   assign(input,'data.in'); reset(input);
   assign(output,'right.out'); rewrite(output);
   readln(n,m);
   for i:= to n do read(a[i]);
   fillchar(f,sizeof(f),);
   opt[n]:=;
   pre[n]:=n;
   f[a[n]]:=n;
   for i:=n- downto  do begin
     opt[i]:=opt[i+]+;
     pre[i]:=pre[i+];
     if (f[a[i]]>)and(f[a[i]]-i<opt[i]) then begin
        opt[i]:=f[a[i]]-i;
        pre[i]:=f[a[i]]-;
     end;
     f[a[i]]:=i;
   end;
   fillchar(rmq,sizeof(rmq),);
   for i:= to  n do rmq[i,]:=opt[i];
   i:=;t:=;
   while t<=n do begin
     for j:= to n-t+ do begin
       if rmq[j,i-]>rmq[j+( shl (i-)),i-] then rmq[j,i]:=rmq[j,i-]
       else rmq[j,i]:=rmq[j+( shl (i-)),i-]
     end;
     inc(i);
     t:=t*;
   end;
   for i:= to m do begin
     readln(l,r);
     inc(l);inc(r);
     if l>r then begin
        j:=l;l:=r;r:=j;
     end;
     keypoint:=find(l,r);
     ans:=;
     if keypoint>l then ans:=findmax(l,keypoint-);
     if (keypoint<=r)and(r-keypoint+>ans) then begin
        ans:=r-keypoint+;
     end;
     writeln(ans);
   end;
   close(input);
   close(output);
 end.