洛谷 2898 [USACO08JAN]haybale猜测Haybale Guessing

题目：
https://www.luogu.org/problemnew/show/2898

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int MAXN=6000001;int n,jl,jr,bl,br,T,l,r;int b[MAXN],delta[MAXN];bool flag;struct hh {int l,r,c;}ma[MAXN],ss[MAXN];struct sh {int l,r;}tree[MAXN];inline bool cmp(hh a,hh b) {return a.c>b.c;}inline int max(int a,int b) { return a>b?a:b;}inline int min(int a,int b) {return a<b?a:b;}inline int read(){    int ss=0;    char c=getchar();    while(c<'0' || c>'9') c=getchar();    while(c>='0' && c<='9') ss=ss*10+c-'0',c=getchar();    return ss;}inline void build_tree(int now,int l,int r){    int mid=(l+r)>>1;    tree[now].l=l,tree[now].r=r;    b[now]=0,delta[now]=0;    if(l==r) return;    build_tree(now<<1,l,mid);    build_tree(now<<1|1,mid+1,r);    b[now]=b[now<<1]+b[now<<1|1];    return;}inline void push(int now){    if(delta[now])    {        b[now<<1]=tree[now<<1].r-tree[now<<1].l+1;        b[now<<1|1]=tree[now<<1|1].r-tree[now<<1|1].l+1;        delta[now<<1]=delta[now<<1|1]=1;        delta[now]=0;    }    return;}inline void change(int now,int l,int r,int v){    int mid=(tree[now].r+tree[now].l)>>1;    if(b[now]==tree[now].r-tree[now].l+1) return;    if(tree[now].l>=l && tree[now].r<=r)     { b[now]=tree[now].r-tree[now].l+1,delta[now]=v;return; }    push(now);    if(l<=mid) change(now<<1,l,r,v);    if(r>=mid+1) change(now<<1|1,l,r,v);    b[now]=b[now<<1]+b[now<<1|1];    return;}inline int query(int now,int l,int r){    int ans=0,mid=(tree[now].l+tree[now].r)>>1;    if(tree[now].l>=l && tree[now].r<=r) return b[now];    push(now);    if(l<=mid) ans+=query(now<<1,l,r);    if(r>=mid+1) ans+=query(now<<1|1,l,r);    return ans;}inline bool check(int x){    memset(b,0,sizeof(b));    memset(delta,0,sizeof(delta));    for(int i=1;i<=x;i++) ss[i]=ma[i];    sort(ss+1,ss+x+1,cmp);//排序，从大到小;    br=jr=ss[1].r,bl=jl=ss[1].l;    for(int i=2;i<=x;i++)    {        if(ss[i].c==ss[i-1].c)        {            if(ss[i].l>br || ss[i].r<bl) {flag=1;return false;}//最小值相同的区域没有交集，不合法；            br=max(br,ss[i].r),jr=min(jr,ss[i].r);            bl=min(bl,ss[i].l),jl=max(jl,ss[i].l);        }        else        {            if(query(1,jl,jr)>=jr-jl+1) {flag=1;return false;}//交集所在区域已经染过色，不合法；            change(1,bl,br,1);//将并集全部染色，如图2；            jl=bl=ss[i].l,jr=br=ss[i].r;        }    }    if(query(1,jl,jr)>=jr-jl+1)    {        flag=1;        return false;    }    else return true;}void solve(){    n=read(),T=read();    for(int i=1;i<=T;i++)         ma[i].l=read(),ma[i].r=read(),ma[i].c=read();    build_tree(1,1,n);    l=1,r=T+1;    while(r - l > 1)    {        int mid=(l+r)>>1;        if(check(mid)) l=mid;        else r=mid;    }    if(flag) printf("%d\n",r);    else puts("0");    return;}int main(){    solve();    return 0;}