minabs.cpp

//search the element which has the minimal abs value in an ascending array
#include <iostream>
#include <cmath>
#include <vector>

using namespace std;

int minabs(vector<int> &a, int start, int end){
    if(start+1 == end){
        return a[start];
    }else if(start+2 == end){
        return abs(a[start]) < abs(a[start+1]) ? a[start] : a[start+1];
    }else if(a[start] * a[end-1] > 0){
        return abs(a[start]) < abs(a[end-1]) ? a[start] : a[end-1];
    }else{
        int middle = (start+end)/2;
        int leftmin = minabs(a, start, middle);
        int rightmin = minabs(a,middle, end);
        return abs(leftmin)< abs(rightmin)?leftmin:rightmin;
    }
}

int main(){
    vector<int> array;
    int buf = 0;
    while(cin>>buf){
        array.push_back(buf);
    }
    cout << minabs(array, 0, array.size()) << endl;
}