3SUM

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

a = [int(x) for x in input().split()]
sorted = []

for i in range(n): sorted.append([a[i], i + 1])

sorted.sort()
found = False
i = 0
r = n - 1
l = 1
while r > 0 and l < n and not found:
    sum3 = sorted[i][0] + sorted[r][0] + sorted[l][0]
    if sum3 < x: l += 1
    if l == i: l += 1
    if sum3 > x: r -= 1
    while r == i or r == l: r-=1
    if sum3 == x: 
        print( sorted[i][1], sorted[r][1], sorted[l][1])
        found = True
if not found: 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: WRONG ANSWER

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: WRONG ANSWER