//#include "prize.h"
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
static const int max_q = 10000;
static int n;
static int query_count = 0;
static vector<int> g;
static vector<vector<int> > rank_count;
int find_best(int n);
std::vector<int> ask(int i);
int subtask0(int n) {
std::vector<int> ans;
for(int i=0; i<n; i++) {
ans = ask(i);
if(ans[0]+ans[1]==0) return i;
}
}
int subtask1(int n){
int start=0, end=n-1;
while (start<end) {
int mid = (start+end)/2;
vector<int> ans = ask(mid);
if (!ans[0] && !ans[1]) return mid;
else if (!ans[0]) start=mid+1;
else end = mid-1;
}
return start;
}
// int bSearch(int start, int end, std::vector<int>& sAns, std::vector<int>& eAns, int maxVal) {
// printf("start=%d, end=%d, ",start,end);
// printf("sAns[%d]={%d,%d}, ",start,sAns[0],sAns[1]);
// printf("eAns[%d]={%d,%d}\n ",start,eAns[0],eAns[1]);
// int result = -1;
// if (eAns[0]==sAns[0]) return -1;
// int mid = (start+end+1)/2;
// printf("mid=%d ",mid);
// vector<int> mAns = ask(mid);
// if (mAns[0]+mAns[1]==0) return mid;
// int midL=mid, midR=mid;
// if(mAns[0]+mAns[1]<maxVal) {
// midL = start;
// for(int i=mid-1; i>start; i--) {
// mAns = ask(i);
// if(mAns[0]+mAns[1]==0) return i;
// if(mAns[0]+mAns[1]==maxVal) {midL=i; break;}
// }
// midR = end;
// for(int i=mid+1; i<end; i++) {
// mAns = ask(i);
// if(mAns[0]+mAns[1]==0) return i;
// if(mAns[0]+mAns[1]==maxVal) {midR=i; break;}
// }
// }
// printf("midL=%d, midR=%d\n",midL,midR);
// if (start<midL) result = bSearch(start,midL,sAns,mAns,maxVal);
// if (result != -1) return result;
// if(midR<end) return bSearch(midR,end,mAns,eAns,maxVal);
// return -1;
// }
int bSearch(int start, int end, std::vector<int>& sAns, std::vector<int>& eAns) {
printf("start=%d, end=%d, ",start,end);
printf("sAns={%d,%d}, ",sAns[0],sAns[1]);
printf("eAns={%d,%d}\n ",eAns[0],eAns[1]);
int result = -1;
if (eAns[0]==sAns[0]) return -1;
int mid = (start+end+1)/2;
printf("mid=%d, ",mid);
vector<int> mAns = ask(mid);
if (mAns[0]+mAns[1]==0) return mid;
int midL=mid, midR=mid;
vector<int> midLAns = mAns, midRAns = mAns;
while(sAns[0]+sAns[1]!=midLAns[0]+midLAns[1] && start + 1 < midL) {
if (sAns[0]+sAns[1] < midLAns[0]+midLAns[1]) {
sAns = ask(++start);
if (sAns[0]+sAns[1]==0) return start;
}
else {
midLAns = ask(--midL);
if (midLAns[0]+midLAns[1]==0) return midL;
}
}
while(midRAns[0]+midRAns[1]!=eAns[0]+eAns[1] && midR + 1 < end) {
if (midRAns[0]+midRAns[1] < eAns[0]+midRAns[1]) {
sAns = ask(++midR);
if (midRAns[0]+midRAns[1]==0) return midR;
}
else {
eAns = ask(--end);
if (eAns[0]+eAns[1]==0) return end;
}
}
printf("midL=%d, midR=%d\n",midL,midR);
if (start + 1 < midL) result = bSearch(start,midL,sAns,midLAns);
if (result != -1) return result;
if(midR + 1 < end) return bSearch(midR,end,midRAns,eAns);
return -1;
}
int find_best(int n) {
// if (n<=5000) {return subtask0(n);}
// int m = min(500,n), maxVal=0, maxIdx=-1;
// for(int i=0; i<m; i++) {
// ans[i] = ask(i);
// int sum = ans[i][0]+ans[i][1];
// // if(sum==0) return i;
// if (maxVal<sum) {maxVal=sum; maxIdx=i;}
// }
// printf("maxVal:%d, maxIdx:%d\n",maxVal,maxIdx);
int start=0, end=n-1;
vector<int> sAns=ask(start), eAns=ask(end);
if (sAns[0]+sAns[1]==0) return start;
if (eAns[0]+eAns[1]==0) return end;
while(sAns[0]+sAns[1]!=eAns[0]+eAns[1]) {
if (sAns[0]+sAns[1] < eAns[0]+eAns[1]) {
sAns = ask(++start);
if (sAns[0]+sAns[1]==0) return start;
}
else {
eAns = ask(--end);
if (eAns[0]+eAns[1]==0) return end;
}
}
// assert sAns[0]+sAns[1]==eAns[0]+eAns[1] && start < end;
return bSearch(start,end,sAns,eAns);
}
