[SDOI2009]HH的项链-树状数组/线段树

树状数组：

 #include<bits/stdc++.h>
 using namespace std;
 const int maxn = ;
 int id[maxn],tree[maxn],vis[maxn],num[maxn];
 int n,m;
 struct Tree{
     int l,r;
     int pos;
 };
 Tree a[maxn];
 int buf[];
 inline void read(int &x){
     char ch=getchar(); x=;
     while(ch<'') ch=getchar();
     while(ch>='' && ch<='') x=(x<<)+(x<<)+(ch^),ch=getchar();
 }
 inline void write(int x){
     if(!x){putchar('');putchar(' ');return;}
     register int cnt=;
     while(x)buf[++cnt]=(x%)+,x/=;
     while(cnt)putchar(buf[cnt--]);
     putchar('\n');
 }
 bool cmp(Tree x,Tree y){
     return x.r < y.r;
 }
 int lowbit(int x){
     return x & -x;
 }
 void add(int x,int now){
     while(x <= n){
         tree[x] += now;
         x += lowbit(x);
     }
 }
 int sum(int n){
     int ans = ;
     while(n != ){
         ans += tree[n];
         n -= lowbit(n);
     }
     return ans;
 }
 int main(){
     read(n);
     for(int i = ;i <= n;i++)
         read(id[i]);
     read(m);
     for(int i = ;i <= m;i++){
         read(a[i].l);
         read(a[i].r);
         a[i].pos = i;
     }
     sort(a+,a++m,cmp);
     int next = ;
     for(int i = ;i <= m;i++){
         for(int j = next;j <= a[i].r;j++){
             if(vis[id[j]])
                 add(vis[id[j]],-);
             add(j,);
             vis[id[j]] = j;
         }
         next = a[i].r+;
         num[a[i].pos] = sum(a[i].r)-sum(a[i].l-);
     }
     for(int i = ;i <= m;i++)
         write(num[i]);
     return  ;
 }

线段树：

 #include<bits/stdc++.h>
 using namespace std;
 const int maxn = 5e6+;
 struct segment_tree{
     int l,r,s,sum;
 };
 segment_tree ask[maxn<<],tree[maxn<<];
 int next[maxn],pre[maxn],a[maxn],x[maxn],n,m;
 int buf[];
 inline void read(int &x){
     char ch=getchar(); x=;
     while(ch<'') ch=getchar();
     while(ch>='' && ch<='') x=(x<<)+(x<<)+(ch^),ch=getchar();
 }
 inline void write(int x){
     if(!x){putchar('');putchar(' ');return;}
     register int cnt=;
     while(x)buf[++cnt]=(x%)+,x/=;
     while(cnt)putchar(buf[cnt--]);
     putchar('\n');
 }
 bool cmp1(segment_tree x,segment_tree y){
     if (x.l == y.l)return x.r < y.r;
     else return x.l < y.l;
 }
 bool cmp2(segment_tree x,segment_tree y){
     return x.s < y.s;
 }
 inline void pushup(int root){
     tree[root].sum = tree[root<<].sum+tree[root<<|].sum;
 }
 inline void build(int root,int l,int r){
     tree[root].l = l;
     tree[root].r = r;
     if(l == r){
         tree[root].sum = a[l];
         return;
     }
     int mid = (l+r)>>;
     build(root<<,l,mid);
     build(root<<|,mid+,r);
     pushup(root);
 }
 inline void update(int root,int k){
     if (tree[root].l == k && tree[root].r == k){
         a[k] = ;
         tree[root].sum = a[k];
         return;
     }
     int mid = (tree[root].l+tree[root].r)>>;
     if(k <= mid)update(root<<,k);
     else update(root<<|,k);
     pushup(root);
 }
 inline int query(int root,int l,int r){
     if(tree[root].l == l && tree[root].r == r)
         return tree[root].sum;
     int mid = (tree[root].l+tree[root].r)>>;
     if(r <= mid)return query(root<<,l,r);
     else
         if(l > mid)return query(root<<|,l,r);
         else return(query(root<<,l,mid)+query(root<<|,mid+,r));
 }
 int main(){
     read(n);
     for(register int i = ;i <= n;i++){
         read(x[i]);
         next[pre[x[i]]] = i;
         if(!pre[x[i]])a[i] = ;
         pre[x[i]] = i;
     }
     build(,,n);
     scanf("%d",&m);
     for(register int i = ;i <= m;i++){
         read(ask[i].l);
         read(ask[i].r);
         ask[i].s = i;
     }
     sort(ask+,ask+m+,cmp1);
     ask[].l = ;
     for(register int i = ;i <= m;i++){
         if(ask[i-].l != ask[i].l)
             for(register int j = ask[i-].l;j <= ask[i].l-;j++)
                 if(next[j])update(,next[j]);
         ask[i].sum = query(,ask[i].l,ask[i].r);
     }
     sort(ask+,ask+m+,cmp2);
     for(register int i=;i<=m;i++)
         write(ask[i].sum);
     return ;
 }

别问我为什么补贴出来分块做法...

因为没学懂！！！没打出来！！！好不容易打出来，给我超时！！！气死了！！！