[bzoj1594]猜数游戏

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define int long long
using namespace std;
inline int read()
{
    int f=1,ans=0;char c;
    while(c<‘0‘||c>‘9‘){if(c==‘-‘)f=-1;c=getchar();}
    while(c>=‘0‘&&c<=‘9‘){ans=ans*10+c-‘0‘;c=getchar();}
    return f*ans;
}
struct node{
    int l,r,minn;
}x[10000001],st[10000001];
int flag[8000001],n,q,maxn,inf=(int)1<<61;
bool cmp(node x1,node x2){return x1.minn>x2.minn;}
void pushdown(int k,int l,int r){
    if(!flag[k]) return;
    flag[k<<1]=flag[k<<1|1]=1;
    flag[k]=0;return;
}
void update(int k,int l,int r,int x,int y){
//    cout<<x<<" "<<y<<endl;
    if(x<=l&&r<=y){flag[k]=1;return;}
    pushdown(k,l,r);
    int mid=l+r>>1;
    if(x<=mid) update(k<<1,l,mid,x,y);
    if(mid<y) update(k<<1|1,mid+1,r,x,y);
    flag[k]=flag[k<<1]&flag[k<<1|1];
    return;
}
int query(int k,int l,int r,int x,int y){
    if(x<=l&&r<=y) return flag[k];
    pushdown(k,l,r);
    int mid=l+r>>1;
    int kkk=1;
    if(x<=mid) kkk&=query(k<<1,l,mid,x,y);
    if(mid<y) kkk&=query(k<<1|1,mid+1,r,x,y);
    flag[k]=flag[k<<1]&flag[k<<1|1];
    return kkk; 
}
bool check(int len){
//    cout<<"len:"<<len<<endl;return 0;
    memset(flag,0,sizeof(flag));
    for(int i=1;i<=len;i++) st[i]=x[i];
    sort(st+1,st+len+1,cmp);
    int j;
    for(int i=1;i<=len;i=j+1){
        j=i;
        while(j<=len&&st[j].minn==st[i].minn) j++;--j;
        int l1=inf,r1=inf,l2=0,r2=0;
        for(int k=i;k<=j;k++){
            
            l1=min(l1,st[k].l);l2=max(l2,st[k].l);
            r1=min(r1,st[k].r),r2=max(r2,st[k].r);
        }
        if(l2>r1) return 0;
        if(query(1,1,n,l2,r1)) return 0;
        update(1,1,n,l1,r2);
    }return 1;
}
signed main()
{
    n=read(),q=read();
    for(int i=1;i<=q;i++) {
        x[i].l=read(),x[i].r=read(),x[i].minn=read();
    }
    int l=1,r=q,mid;
    while(l<=r){
        mid=l+r>>1;
        if(check(mid)) maxn=max(maxn,mid),l=mid+1;
        else r=mid-1;
    }
    if(maxn!=q) cout<<maxn+1;
    else cout<<0;
}