题解

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cctype>
using namespace std;
const int N=1e6+10;
int T,n,a[N],w[N],q1[N],q2[N];
int read(){
	int x=0,f=1;char c=getchar();
	while(!isdigit(c)){if(c=='-')f=-f;c=getchar();}
	while(isdigit(c)){x=(x<<1)+(x<<3)+c-'0';c=getchar();}
	return x*f;
}
bool cmp(int x,int y)
{return (w[x]==w[y])?x<y:w[x]<w[y];}
void solve(){
	int h1=1,t1=n,h2=1,t2=0,v,p;T--;
	for(int i=1;i<=n;i++)w[q1[n-i+1]=i]=a[i];
	while(1){
		if(t1-h1+1+t2-h2+1==2){printf("%d\n",1);return;}
		if(t2-h2+1<=0||t1-h1+1>0&&cmp(q2[h2],q1[h1])){
			v=w[p=q1[h1]];p=q1[h1];h1++;
			if(t2-h2+1<=0||t1-h1+1>0&&cmp(q1[t1],q2[t2]))v-=w[q1[t1]],t1--;
			else v-=w[q2[t2]],t2--;
		}
		else{
			v=w[p=q2[h2]];h2++;
			if(t2-h2+1<=0||t1-h1+1>0&&cmp(q1[t1],q2[t2]))v-=w[q1[t1]],t1--;
			else v-=w[q2[t2]],t2--;
		}
		w[p]=v;
		if((t2-h2+1<=0||cmp(p,q2[t2]))&&(t1-h1+1<=0||cmp(p,q1[t1])))
			{q2[++t2]=p;break;}
		q2[++t2]=p;
	}
	int cnt=0,f=t2-h2+1+t1-h1+1;
	while(1){
		cnt++;
		if(t1-h1+1+t2-h2+1==2){printf("%d\n",f+(cnt&1));return;}
		if(t2-h2+1<=0||t1-h1+1>0&&cmp(q2[h2],q1[h1])){
			v=w[p=q1[h1]];p=q1[h1];h1++;
			if(t2-h2+1<=0||t1-h1+1>0&&cmp(q1[t1],q2[t2]))v-=w[q1[t1]],t1--;
			else v-=w[q2[t2]],t2--;
		}
		else{
			v=w[p=q2[h2]];h2++;
			if(t2-h2+1<=0||t1-h1+1>0&&cmp(q1[t1],q2[t2]))v-=w[q1[t1]],t1--;
			else v-=w[q2[t2]],t2--;
		}
		w[p]=v;
		if((t2-h2+1<=0||cmp(p,q2[t2]))&&(t1-h1+1<=0||cmp(p,q1[t1])))
			{q2[++t2]=p;continue;}
		printf("%d\n",f+(cnt&1));return;
	}
	return;
}
int main()
{
	T=read();n=read();
	for(int i=1;i<=n;i++)a[i]=read();
	solve();
	while(T){
		int k=read();
		while(k--){
			int x=read(),w=read();
			a[x]=w;
		}
		solve();
	}
	return 0;
}