Gss1

int mid = i + (j-1)/2

Still in shock 4r making mistake lyk dat ..

@leppy : thnks for the help..

but now it's showing wrong answer ...

Happy to help. Work with it a bit. Post your updated code if you can't figure it out.

managed to avoid WA but now got stuck on TLE ...

#include <bits/stdc++.h>
using namespace std;
#define MAX 50005
#define ll long long
int sn,arr[MAX];
struct node{
    ll best,sum,lft,ryt;
	node(ll a = 0){
		best = sum = lft = ryt = a;
	}
	void merge(node a,node b){
		sum = a.sum+b.sum;
		lft = max(a.lft, a.sum+b.lft);
		ryt = max(b.ryt, a.ryt+b.sum);
		best = max(sum, max(lft,ryt) );
	}
}*segtree=NULL;
node query(int i,int j,int ri,int rj,int curr){
	if(rj<i || ri>j)
		return node();
	if(ri<=i&&rj>=j)
		return segtree[curr];
	int mid = i + (j-i)/2,l=2*curr+1;
    node a,b,temp;
	a = query(i,mid,ri,rj,l);
    b = query(mid+1,j,ri,rj,l+1);
    temp.merge(a,b);
    return temp;
}
void build(int i,int j,int curr){
	if(i>j)
		return;
	if(i==j){
		segtree[curr] = node(arr[i]);
		return;
	}
	int l = 2*curr+1,mid=i +(j-i)/2,r = 2*curr+2;
	build(i,mid,l);
	build(mid+1,j,r);
	segtree[curr].merge(segtree[l],segtree[r]);
}
void init(int n){
	sn = ceil(log2(n)+1);
	sn = 2*pow(2,sn);
	segtree = (node*)malloc(sn * sizeof(node));
	build(0,n-1,0);
}
int main() {
	int n,q,ri,rj;
	cin>>n;
	for(int i=0;i<n;i++)
		cin>>arr[i];
	init(n);
	build(0,n-1,0);
	cin>>q;
	while(q--){
		cin>>ri>>rj;
		node temp = query(0,n-1,ri-1,rj-1,0);
        cout<<temp.best<<'\n';
	}
	free(segtree);
	return 0;
}

can you improve this code?? thnks for it!!

Cin/cout are slow.

used scanf & printf .. now it's giving wrong answer

If you're still having an issue, please post your updated code and edit the previous posts and remove the code.

here's the updated code:

#include <bits/stdc++.h>
using namespace std;
#define MAX 50005
#define ll long long
int sn,arr[MAX];
struct node{
    ll best,sum,lft,ryt;
	node(ll a = 0){
		best = sum = lft = ryt = a;
	}
	void merge(node a,node b){
		sum = a.sum+b.sum;
		lft = max(a.lft, a.sum+b.lft);
		ryt = max(b.ryt, a.ryt+b.sum);
		best = max(a.ryt+b.lft, max(a.best,b.best));
	}
}*segtree=NULL;
node query(int i,int j,int ri,int rj,int curr){
	if(rj<i || ri>j)
		return node();
	if(ri<=i&&rj>=j)
		return segtree[curr];
	int mid = i + (j-i)/2,l=2*curr+1;
	if(j<=mid)
		return query(i,j,ri,rj,l);
	else if(i>mid)
		return query(i,j,ri,rj,l+1);
	else{
    	node a,b,temp;
		a = query(i,mid,ri,rj,l);
    	b = query(mid+1,j,ri,rj,l+1);
    	temp.merge(a,b);
	    return temp;
	}
}
void build(int i,int j,int curr){
	if(i>j)
		return;
	if(i==j){
		segtree[curr] = node(arr[i]);
		return;
	}
	int l = 2*curr+1,mid=i +(j-i)/2,r = 2*curr+2;
	build(i,mid,l);
	build(mid+1,j,r);
	segtree[curr].merge(segtree[l],segtree[r]);
}
void init(int n){
	sn = ceil(log2(n)+1);
	sn = 2*pow(2,sn);
	segtree = (node*)malloc(sn * sizeof(node));
	build(0,n-1,0);
}
int main() {
	int n,q,ri,rj;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
		scanf("%d",&arr[i]);
	init(n);
	build(0,n-1,0);
	scanf("%d",&q);
	while(q--){
		scanf("%d %d",&ri,&rj);
		node temp = query(0,n-1,ri-1,rj-1,0);
        printf("%lld\n",temp.best);
	}
	free(segtree);
	return 0;
}

Why do you run build twice?

#include
using namespace std;
int main()
{
int n;
cin>>n;
int a[2n + 1];
for(int i=0;i<n;i++)
cin>>a[n+i];
for(int i=n-1;i>=1;i–)
a[i] = max(a[2i],a[2*i + 1]);
int q;
cin>>q;
for(;q>0;q–)
{
int l,r;
cin>>l>>r;
l–;
int res = a[n+l];
for(l+=n,r+=n ; l<r && l>=1 && r>1;l/=2,r/=2)
{
if(l%2 != 0)
{
res = max(res,a[l]);
l++;
}
if(r%2 != 0)
{
r–;
res = max(res,a[r]);
}
}
cout<<res<<"\n";
}
return 0;

}

Can anyone debug my code,. Got WA.