frequent values

#include<bits/stdc++.h>
using namespace std;


const int INF = 0x3f3f3f3f;
const double EPS = 1e-10;
const int MAX = 1<<17;

struct NODE { int mfreq, lfreq, rfreq; };

int a[MAX];
struct NODE Tree[MAX<<1];

void init(int Node, int i, int j)
{
	if(i==j)
	{
		Tree[Node].lfreq = Tree[Node].rfreq = Tree[Node].mfreq = 1;
		return;
	}
	int m = (i + j)>>1;
	init(Node<<1, i, m);
	init((Node<<1)+1, m+1, j);
	if(a[m]==a[m+1])
	{
		Tree[Node].lfreq = Tree[Node<<1].lfreq + Tree[(Node<<1)+1].lfreq * (a[i]==a[m]);
		Tree[Node].rfreq = Tree[(Node<<1)+1].rfreq + Tree[Node<<1].rfreq * (a[j]==a[m+1]);
		int temp = Tree[Node<<1].rfreq + Tree[(Node<<1)+1].lfreq;
		Tree[Node].mfreq = max(temp, max(Tree[Node<<1].mfreq, Tree[(Node<<1)+1].mfreq));
	}
	else
	{
		Tree[Node].lfreq = Tree[Node<<1].lfreq;
		Tree[Node].rfreq = Tree[(Node<<1)+1].rfreq;
		Tree[Node].mfreq = max(Tree[Node<<1].mfreq, Tree[(Node<<1)+1].mfreq);
	}
}

int query(int Node, int i, int j, int u, int v)
{
	if(u==i && v==j)
		return Tree[Node].mfreq;
	int m = (i+j)>>1;
	if(v <= m)
		return query(Node<<1, i, m, u, v);
	if(u > m)
		return query((Node<<1)+1, m+1, j, u, v);
	int leftv = query(Node<<1, i, m, u, m);
	int rightv = query((Node<<1)+1, m+1, j, m+1, v);
	if(a[m]==a[m+1])
	{
		int temp = min(Tree[Node<<1].rfreq, m-u+1) + min(Tree[(Node<<1)+1].lfreq, v-m);
		return max(temp, max(rightv, leftv));
	}
	else
		return max(leftv, rightv);
}

int main()
{
	int n, q, i, u, v;
	while(scanf("%d", &n)==1 && n)
	{
		scanf("%d", &q);
		for(i = 0; i < n; i++)
			scanf("%d", &a[i]);
		init(1, 0, n-1);
		for(i = 0; i < q; i++)
		{
			scanf("%d%d", &u, &v);
			if(u==v)
				printf("1\n");
			else
				printf("%d\n", query(1, 0, n-1, --u, --v));
		}
	}
	return 0;
}