C. Not Equal on a Segment

You are given array a with n integers and m queries. The i-th query is given with three integers li, ri, xi.

For the i-th query find any position pi (li ≤ pi ≤ ri) so that api ≠ xi.

The first line contains two integers n, m (1 ≤ n, m ≤ 2·105) — the number of elements in a and the number of queries.

The second line contains n integers ai (1 ≤ ai ≤ 106) — the elements of the array a.

Each of the next m lines contains three integers li, ri, xi (1 ≤ li ≤ ri ≤ n, 1 ≤ xi ≤ 106) — the parameters of the i-th query.

Print m lines. On the i-th line print integer pi — the position of any number not equal to xi in segment [li, ri] or the value  - 1 if there is no such number.

Code

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int maxn=1e6;
int a[maxn],n,q;
struct tree
{
    int l,r;
    long long maxx;
    long long minn;
}t[4*maxn+2];
void bulid(int p,int l,int r)
{
    t[p].l=l;
    t[p].r=r;
    if(l==r)
    {
        t[p].maxx=a[l];
        t[p].minn=a[l];
        return;
    }
    int mid=l+r>>1;
    bulid(p*2,l,mid);
    bulid(p*2+1,mid+1,r);
    t[p].maxx=max(t[p*2].maxx,t[p*2+1].maxx);
    t[p].minn=min(t[p*2].minn,t[p*2+1].minn);
}
//线段树二分
//[x,y]中第一个大于z的下标
long long ask(int p,int x,int y,int z)
{
    if(t[p].l==x&&t[p].r==y)
    {
        if(t[p].maxx<=z)return -1;
        else
        {
            if(t[p].l==t[p].r)return t[p].l;
            int mid=(t[p].l+t[p].r)>>1;
            if(t[p*2].maxx>z)return ask(p*2,x,mid,z);
            else return ask(p*2+1,mid+1,y,z);
        }
    }
    int mid=(t[p].l+t[p].r)>>1;
    if(y<=mid)return ask(p*2,x,y,z);
    else if(x>mid) return ask(p*2+1,x,y,z);
    else
    {
        int pos=ask(p*2,x,mid,z);
        if(pos==-1)return ask(p*2+1,mid+1,y,z);
        else return pos;
    }
}
long long ask2(int p,int x,int y,int z)
{
    if(t[p].l==x&&t[p].r==y)
    {
        if(t[p].minn>=z)return -1;
        else
        {
            if(t[p].l==t[p].r)return t[p].l;
            int mid=(t[p].l+t[p].r)>>1;
            if(t[p*2].minn<z)return ask2(p*2,x,mid,z);
            else return ask2(p*2+1,mid+1,y,z);
        }
    }
    int mid=(t[p].l+t[p].r)>>1;
    if(y<=mid)return ask2(p*2,x,y,z);
    else if(x>mid) return ask2(p*2+1,x,y,z);
    else
    {
        int pos=ask2(p*2,x,mid,z);
        if(pos==-1)return ask2(p*2+1,mid+1,y,z);
        else return pos;
    }
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin>>n>>q;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
    }
    bulid(1,1,n);
    while(q--)
    {
        int op,x,d,l,r;
        cin>>l>>r>>x;
        int ans1=ask(1,l,r,x);
        int ans2=ask2(1,l,r,x);
        //cout<<ans1<<" "<<ans2<<"\n";
        if(ans1==-1&&ans2==-1)cout<<-1<<"\n";
        else if(ans1!=-1)cout<<ans1<<"\n";
        else cout<<ans2<<"\n";
    }
    return 0;
}