Adventofcode/Day1part2.cpp at main · Saketh1100/Adventofcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
int main()
{

    fstream indata;
    indata.open("day1data");
    vector<int> v;
    int p;
    if (indata.fail())
    {
        cout << "some thing is wrong";
    }
    while (indata >> p)
    {
        v.push_back(p);
    }

    sort(v.begin(), v.end());

    int l = v.size() - 1;
    int j=l;
    int count=1;
    int i;
    int a=0;
    int b=0;
    int c=0;


    for(int k=0;k<=l;k++)
    {
        int sum=2020-v[k];
        i=k+1;//because in previous value of k  i which are less than k combinations are already` covered
        j=l;
        while (i < j&&j!=k)
        {
            if (v[i] + v[j] == sum)//using same logic for sum of 2 numbers;
            {

                a=i;
                b=j;
                c=k;
                break;

                count=0;
            }
            else if (v[i] + v[j] < sum)
            {
                i++;
            }
            else if (v[i] + v[j] > sum)
            {
                j--;
            }
        }
        if(count==0)
        {
            break;

        }
    }


    cout << v[a]<<endl<<v[b]<<endl<<v[c] << endl;


    return 0;
}