Selectivo 2 - P3

#include <cstdio>
#include <vector>
#include <iostream>

using namespace std;

bool check(int pos, int p, int q, int it){
    if(it == 0 || q < pos || p > pos) return false;

    int mi = (p + q) >> 1;
    --it;

    if(pos == mi){
        if(it == 0) return true;
        return false;
    }

    if(pos < mi) return check(pos,p,mi - 1,it);
    return check(pos,mi + 1,q,it);
}

int main(){
    int x,it;

    scanf("%d %d",&x,&it);

    vector<int> v;

    for(int i = 0;i < 10000;++i){
        if(check(x,0,i,it)) v.push_back(i + 1);
    }

    int sz = v.size(),ans = 0;
    vector<int> l,r;

    for(int i = 0;i < sz;){
        int e = i + 1;

        while(e < sz && v[e] - v[i] == e - i) ++e;

        l.push_back(v[i]);
        r.push_back(v[e - 1]);

        i = e;
        ++ans;
    }

    printf("%d\n",ans);

    for(int i = 0;i < ans;++i)
        printf("%d %d\n",l[i],r[i]);

    return 0;
}