luogu4093 [HEOI2016/TJOI2016]序列

因为一个变化只会变化一个值，所以

\(dp[i]=max(dp[j])+1,j<i,maxval_j \leq a[i], a[j] \leq minval_i\)

发现跟二维数点问题挺像，树状数组套线段树爽一爽。

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, zdz[100005], zxz[100005], a[100005], uu, vv, cnt, dp[100005], ans, rot[100005];
struct Node{
	int l, r, zdz;
}nd[9000005];
int lb(int x){
	return x&-x;
}
void insert(int &o, int l, int r, int x, int k){
	if(!o)	o = ++cnt;
	if(l==r)	nd[o].zdz = max(nd[o].zdz, k);
	else{
		int mid=(l+r)>>1;
		if(x<=mid)	insert(nd[o].l, l, mid, x, k);
		if(mid<x)	insert(nd[o].r, mid+1, r, x, k);
		nd[o].zdz = max(nd[nd[o].l].zdz, nd[nd[o].r].zdz);
	}
}
int query(int o, int l, int r, int x, int y){
	if(!o)	return 0;
	if(l>=x &&r<=y)	return nd[o].zdz;
	else{
		int mid=(l+r)>>1;
		int re=0;
		if(x<=mid)	re = max(re, query(nd[o].l, l, mid, x, y));
		if(mid<y)	re = max(re, query(nd[o].r, mid+1, r, x, y));
		return re;
	}
}
int main(){
	cin>>n>>m;
	for(int i=1; i<=n; i++){
		scanf("%d", &a[i]);
		zdz[i] = zxz[i] = a[i];
	}
	for(int i=1; i<=m; i++){
		scanf("%d %d", &uu, &vv);
		zdz[uu] = max(zdz[uu], vv);
		zxz[uu] = min(zxz[uu], vv);
	}
	for(int i=1; i<=n; i++){
		for(int j=zxz[i]; j; j-=lb(j))
			dp[i] = max(dp[i], query(rot[j], 1, 100000, 1, a[i]));
		dp[i]++;
		ans = max(ans, dp[i]);
		for(int j=a[i]; j<=100000; j+=lb(j))
			insert(rot[j], 1, 100000, zdz[i], dp[i]);
	}
	cout<<ans<<endl;
	return 0;
}