DiscreteMap.cc

DiscreteMap.cc

#include <cstdio>
#include <iostream>
#include <ctime>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <vector>
#include <map>
#include <algorithm>

using namespace std;

#define print(x) cout << x << endl
#define input(x) cin >> x

template<int map_size>
struct DiscreteMap {
    DiscreteMap(){}
    
    void init(int* i_array, int i_size) 
    {
        int idx = 1;
        memset(m2o, -1, sizeof(m2o));
        o2m.clear();
        sort(i_array, i_array + i_size);
        for (int i = 0; i < i_size; i++) {
            m2o[idx] = i_array[i];
            o2m[i_array[i]] = idx;
            idx++;
        }
    }
    
    int disc(int big)
    {
        if (o2m.find(big) == o2m.end()) {
            return -1;
        }
        return o2m[big];
    }
    
    int undisc(int small)
    {
        if (small >= map_size) {
            return -1;
        }
        return m2o[small];
    }
    
    int m2o[map_size];
    map<int, int> o2m;
};

int main()
{
    DiscreteMap<1000> dmap;
    int tarr[] = {1, 10, 100, 1000, 10000};
    dmap.init(tarr, 5);
    assert(dmap.disc(1) == 1);
    assert(dmap.disc(10) == 2);
    assert(dmap.disc(100) == 3);
    assert(dmap.disc(1000) == 4);
    assert(dmap.disc(10000) == 5);
    
    assert(dmap.undisc(1) == 1);
    assert(dmap.undisc(2) == 10);
    assert(dmap.undisc(3) == 100);
    assert(dmap.undisc(4) == 1000);
    assert(dmap.undisc(5) == 10000);
    return 0;
}