hdu1540/poj2892 线段数区间合并

#include "iostream"
#include "string.h"
#include "stack"
#include "queue"
#include "string"
#include "vector"
#include "set"
#include "map"
#include "algorithm"
#include "stdio.h"
#include "math.h"
#pragma comment(linker, "/STACK:102400000,102400000")
#define ll long long
#define endl ("\n")
#define bug(x) cout<<x<<" "<<"UUUUU"<<endl;
#define mem(a,x) memset(a,x,sizeof(a))
#define mp(x,y) make_pair(x,y)
#define pb(x) push_back(x)
#define ft (frist)
#define sd (second)
#define lrt (rt<<1)
#define rrt (rt<<1|1)
#define len (r-l+1)
using namespace std;
const long long INF = 1e18+1LL;
const int inf = 1e9+1e8;
const int N=1e5+100;
const ll mod=1e9+7;

int n,sum[N<<1],lsum[N<<1],rsum[N<<1],lazy[N<<1];
void push_up(int rt, int m){
    int rm=m>>1, lm=m-rm;
    lsum[rt]=lsum[lrt], rsum[rt]=rsum[rrt];
    if(lsum[rt]==lm){
        lsum[rt]+=lsum[rrt];
    }
    if(rsum[rt]==rm){
        rsum[rt]+=rsum[lrt];
    }
    sum[rt]=max(sum[lrt],sum[rrt]);
    sum[rt]=max(sum[rt],rsum[lrt]+lsum[rrt]);
}

void push_down(int rt, int m){
    int rm=m>>1, lm=m-rm;
    if(lazy[rt]==0){
        lm=rm=0;
    }
    sum[lrt]=lsum[lrt]=rsum[lrt]=lm;
    sum[rrt]=lsum[rrt]=rsum[rrt]=rm;
    lazy[lrt]=lazy[rrt]=lazy[rt];
    lazy[rt]=-1;
}

void creat(int rt, int l, int r){
    if(l==r){
        sum[rt]=lsum[rt]=rsum[rt]=1;
        return;
    }
    lazy[rt]=-1;
    int mid=l+r>>1;
    creat(lrt,l,mid);
    creat(rrt,mid+1,r);
    push_up(rt, len);
}

void update(int rt, int l, int r, int L, int R, int v){
    if(l>=L && r<=R){
        int m=len;
        lazy[rt]=v;
        if(!v) m=0; //cout<<m<<endl;
        sum[rt]=lsum[rt]=rsum[rt]=m;
        return;
    }
    if(lazy[rt]!=-1) push_down(rt, len);
    int mid=l+r>>1;
    if(L<=mid) update(lrt, l, mid, L, R, v);
    if(R>mid) update(rrt, mid+1, r, L, R, v);
    push_up(rt, len);
}

int query(int rt, int l, int r, int x){
    if(l==r) return sum[rt];
    if(lazy[rt]!=-1) push_down(rt, len);
    int mid=l+r>>1;
    if(lsum[rt]>=x) return lsum[rt];
    else if(n-rsum[rt]+1<=x) return rsum[rt];
    else if(mid-rsum[lrt]+1<=x && mid+lsum[rrt] >=x ) return rsum[lrt]+lsum[rrt];
    else if(x<=mid) return query(lrt, l, mid, x);
    else return query(rrt, mid+1, r, x);
}

int main(){
    //ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    char c;
    int x,m;
    while(cin>>n>>m){
        creat(1,1,n);
        int l=0, d[N];
        while(m--){
            cin>>c;
            if(c==‘R‘){
                x=d[l--];
                update(1,1,n,x,x,1);
            }
            else{
                cin>>x;
                if(c==‘D‘){
                    d[++l]=x;
                    update(1,1,n,x,x,0);
                }
                else{
                    cout<<query(1,1,n,x)<<endl;
                }
            }
        }
    }
    return 0;
}