3SUM

n,target = [int(x) for x in input().split()]


numbers = [(int(val), i + 1) for i, val in enumerate(input().split())]

numbers.sort()  

for i in range(n-2):
    left = i+1
    right = n-1
    curr_number = numbers[i][0]
    while left<right:
        result = curr_number + numbers[left][0] + numbers[right][0]
        if result == target:
            print(numbers[i][1],numbers[left][1],numbers[right][1])
            exit()
        elif result > target:
            right -=1
        else :
            left+=1
print("IMPOSSIBLE")

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED