bzoj4552: [Tjoi2016&Heoi2016]排序

二分答案，把大于二分值的变成1，否则变成0，线段树修改，最后查询问位置是1还是0。

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;int read(){    char ch=getchar();int f=0,x=1;    while(ch<'0'||ch>'9'){if(ch=='-') x=-1;ch=getchar();}    while(ch>='0'&&ch<='9'){f=(f<<1)+(f<<3)+ch-'0';ch=getchar();}    return f*x;}int n,m,a[100005],pla;bool now[100005];struct data{    int l;    int r;    int op;}q[100005];struct segtree{    int ls;    int rs;    int sum;    int mark;}tree[400005];int tot=1;void build(int p,int l,int r){    int mid=l+r>>1;    if(l==r)    {        tree[p].sum=now[mid];        tree[p].mark=-1;        return;    }    tree[p].mark=-1;    tree[p].ls=++tot;    tree[p].rs=++tot;    build(tree[p].ls,l,mid);    build(tree[p].rs,mid+1,r);    tree[p].sum=tree[tree[p].ls].sum+tree[tree[p].rs].sum;}int query(int p,int l,int r,int x,int y){    int mid=l+r>>1;    if(l==x&&r==y)    {        return tree[p].sum;    }    if(tree[p].mark!=-1)    {        tree[tree[p].ls].mark=tree[tree[p].rs].mark=tree[p].mark;        tree[tree[p].ls].sum=(mid-l+1)*tree[p].mark;        tree[tree[p].rs].sum=(r-mid)*tree[p].mark;        tree[p].mark=-1;    }    if(y<=mid) return query(tree[p].ls,l,mid,x,y);    else if(x>mid) return query(tree[p].rs,mid+1,r,x,y);    else return query(tree[p].ls,l,mid,x,mid)+query(tree[p].rs,mid+1,r,mid+1,y);}void modify(int p,int l,int r,int x,int y,int k){    if(y<x) return;    int mid=l+r>>1;    if(l==x&&r==y)    {        tree[p].sum=(r-l+1)*k;        tree[p].mark=k;        return;    }    if(tree[p].mark!=-1)    {        tree[tree[p].ls].mark=tree[tree[p].rs].mark=tree[p].mark;        tree[tree[p].ls].sum=(mid-l+1)*tree[p].mark;        tree[tree[p].rs].sum=(r-mid)*tree[p].mark;        tree[p].mark=-1;    }    if(y<=mid) modify(tree[p].ls,l,mid,x,y,k);    else if(x>mid) modify(tree[p].rs,mid+1,r,x,y,k);    else    {        modify(tree[p].ls,l,mid,x,mid,k);        modify(tree[p].rs,mid+1,r,mid+1,y,k);    }    tree[p].sum=tree[tree[p].ls].sum+tree[tree[p].rs].sum;}bool check(int x){    for(int i=1;i<=n;i++)    {        now[i]=(a[i]>=x)?1:0;    }tot=1;    build(1,1,n);    for(int i=1;i<=m;i++)    {        int temp=query(1,1,n,q[i].l,q[i].r);        if(q[i].op==0)        {            modify(1,1,n,q[i].r-temp+1,q[i].r,1);            modify(1,1,n,q[i].l,q[i].r-temp,0);        }        else        {            modify(1,1,n,q[i].l,q[i].l+temp-1,1);            modify(1,1,n,q[i].l+temp,q[i].r,0);        }    }    return query(1,1,n,pla,pla);}int main(){    n=read();m=read();    for(int i=1;i<=n;i++) a[i]=read();    for(int i=1;i<=m;i++)    {        q[i].op=read();q[i].l=read();q[i].r=read();    }    int l=1,r=n,ans;    pla=read();    while(l<=r)    {        int mid=l+r>>1;        if(check(mid))        {            l=mid+1;            ans=mid;        }        else r=mid-1;    }    cout<<ans;}