BZOJ 3289 Mato的文件管理

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莫队+树状数组，需要离散化
#include <cstdio>#include <iostream>#include <cstdlib>#include <algorithm>#include <cmath>using namespace std ;int n,m,sn;int a[50010],b[50010],lens;typedef struct NODE{    int s,t;    int id,ids,ans;}N;N map[50010];int tree[65536],maxlen=1;void init (){    cin >>n;    sn=sqrt (n);    int i;    for (i=1;i<=n;i++){        scanf ("%d",&a[i]);        b[i]=a[i];    }    cin >>m;    for (i=1;i<=m;i++){        scanf ("%d %d",&map[i].s,&map[i].t);        map[i].id=map[i].s/sn;        if (map[i].id>sn) map[i].id=sn;        map[i].ids=i;    }}int lowbit (int x){    return x&(-x);}void add_it (int x,int zf){    int now=x;    while (now<=maxlen) {        tree[now]+=zf;        now+=lowbit (now);    }}int sum (int x){    int cnt=0;    while (x){        cnt+=tree[x];        x-=lowbit (x);    }    return cnt;}int add_head (int x,int zf){    int add=sum(a[x]-1);    add_it (a[x],zf);    return zf*add;}int add_tail (int x,int zf){    int add=sum(maxlen)-sum(a[x]);    add_it (a[x],zf);    return zf*add;}void work (){    int i;    int S=1,T=0;    int ans=0;    for (i=1;i<=m;i++){        while (S<map[i].s){            ans+=add_head (S,-1);            S++;        }        while (S>map[i].s){            S--;            ans+=add_head (S,1);        }        while (T<map[i].t){            T++;            ans+=add_tail (T,1);        }        while (T>map[i].t){            ans+=add_tail (T,-1);            T--;        }        map[i].ans=ans;    }}int cmp (const void *a,const void *b){    N x=*(N *)a,y=*(N *)b;    if (x.id > y.id) return 1;    else {        if (x.id==y.id) {            if (x.t > y.t) return 1;            else return -1;        }        else return -1;    }}int cmp1 (const void *a,const void *b){    return ((N *)a)->ids>((N *)b)->ids ? 1 : -1;}int main (){    init ();    int i;    qsort (map+1,m,sizeof(map[1]),cmp);    sort (b+1,b+1+n);    lens=unique (b+1,b+n+1)-b-1;    for (i=1;i<=n;i++) a[i]=lower_bound (b+1,b+1+lens,a[i])-b;    while (maxlen<map[m].t) maxlen<<=1;    work ();    qsort (map+1,m,sizeof (map[i]),cmp1);    for (i=1;i<=m;i++){        printf ("%d\n",map[i].ans);    }    return 0;}
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