3SUM

import sys
inp = sys.stdin.read().split()

n = int(inp[0])


if n <3 :
    print("IMPOSSIBLE")
    exit()


x = int(inp[1])
ind=0
numbers = []
for i in inp[2:]:
    numbers.append((int(i),ind))
    ind+=1

snumbers = sorted(numbers,key=lambda x: x[0],reverse=True)
#let's start with a naive approach
    
for i in range(n):
    sni = snumbers[i][0]
    if sni >= x :
        continue
    else :
        #probably inverse this loop
        for k in range(i+1,n):
            if sni + snumbers[k][0] >= x or k == n-1 : 
                continue
            else :
                for w in range(k+1,n) :
                    if sni + snumbers[k][0] + snumbers[w][0] == x:
                        print(f"{snumbers[i][1] +1} {snumbers[k][1] +1 } {snumbers[w][1] +1}")
                        exit()
print("IMPOSSIBLE")






#print(ind)

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: TIME LIMIT EXCEEDED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: TIME LIMIT EXCEEDED

Test 14

Verdict: TIME LIMIT EXCEEDED

Test 15

Verdict: TIME LIMIT EXCEEDED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: TIME LIMIT EXCEEDED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: TIME LIMIT EXCEEDED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: TIME LIMIT EXCEEDED

Test 22

Verdict: TIME LIMIT EXCEEDED

Test 23

Verdict: ACCEPTED