Different Integers

链接

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题解

总的不同数字个数减去只在$(l,r)$出现的数字种类，就是答案

代码

#include 
#include 
#include 
#define iinf 0x3f3f3f3f
#define linf (1ll<<60)
#define eps 1e-8
#define maxn 100010
#define maxe 100010
#define cl(x) memset(x,0,sizeof(x))
#define rep(i,a,b) for(i=a;i<=b;i++)
#define drep(i,a,b) for(i=a;i>=b;i--)
#define em(x) emplace(x)
#define emb(x) emplace_back(x)
#define emf(x) emplace_front(x)
#define fi first
#define se second
#define de(x) cerr<<#x<<" = "<
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll read(ll x=0)
{
    ll c, f(1);
    for(c=getchar();!isdigit(c);c=getchar())if(c=='-')f=-f;
    for(;isdigit(c);c=getchar())x=x*10+c-0x30;
    return f*x;
}
struct BIT
{
    ll bit[maxn], n;
    void init(int N){n=N;for(int i=1;i<=n;i++)bit[i]=0;}
    ll lowbit(ll x){return x&(-x);}
    void add(ll pos, ll v)
    {
        for(;pos<=n;pos+=lowbit(pos))bit[pos]+=v;
    }
    ll sum(ll pos)
    {
        ll ans(0);
        for(;pos;pos-=lowbit(pos))ans+=bit[pos];
        return ans;
    }
}bit;
ll n, q, fst[maxn], lst[maxn], a[maxn], l[maxn], r[maxn], id[maxn], ans[maxn];
int main()
{
    ll i;
    while(~scanf("%lld%lld",&n,&q))
    {
        rep(i,1,n)a[i]=read();
        rep(i,1,n)fst[i]=lst[i]=0;
        rep(i,1,n)lst[a[i]]=i;
        drep(i,n,1)fst[a[i]]=i;
        bit.init(n);
        vector<pll> v;
        rep(i,1,n)if(fst[a[i]]==i)v.emb(pll(i,lst[a[i]]));
        sort(v.begin(),v.end(),[](pll p1, pll p2){return p1>p2;});
        rep(i,1,q)l[i]=read(), r[i]=read(), id[i]=i;
        sort(id+1,id+q+1,[](ll x, ll y){return l[x]>l[y];});
        auto it = v.begin();
        rep(i,1,q)
        {
            while(it!=v.end() and it->first>l[id[i]])
            {
                bit.add(it->second,+1);
                it++;
            }
            ans[id[i]] = bit.sum(r[id[i]]-1);
        }
        rep(i,1,q)printf("%lld\n",v.size()-ans[i]);
    }
    return 0;
}