CSES - Aalto Competitive Programming 2026 - wk7 - Mon

Submission details
Task:	3SUM
Sender:	aalto26gm_007
Submission time:	2026-10-19 17:14:35 +0300
Language:	Python3 (PyPy3)
Status:	READY
Result:	ACCEPTED

Test results
test	verdict	time
#1	ACCEPTED	0.04 s	details
#2	ACCEPTED	0.04 s	details
#3	ACCEPTED	0.04 s	details
#4	ACCEPTED	0.04 s	details
#5	ACCEPTED	0.04 s	details
#6	ACCEPTED	0.04 s	details
#7	ACCEPTED	0.04 s	details
#8	ACCEPTED	0.04 s	details
#9	ACCEPTED	0.04 s	details
#10	ACCEPTED	0.13 s	details
#11	ACCEPTED	0.13 s	details
#12	ACCEPTED	0.06 s	details
#13	ACCEPTED	0.13 s	details
#14	ACCEPTED	0.13 s	details
#15	ACCEPTED	0.13 s	details
#16	ACCEPTED	0.06 s	details
#17	ACCEPTED	0.07 s	details
#18	ACCEPTED	0.05 s	details
#19	ACCEPTED	0.13 s	details
#20	ACCEPTED	0.06 s	details
#21	ACCEPTED	0.13 s	details
#22	ACCEPTED	0.13 s	details
#23	ACCEPTED	0.04 s	details

Code

# import sys
# from bisect import bisect_left
# def main():
#     data = sys.stdin.buffer.read().split()
#     n, target = int(data[0]), int(data[1])
#     if target<=2:
#         print("IMPOSSIBLE")
#         exit()

#     l = list(zip(list(map(int, data[2:])), range(1,n+1)))
#     # print(l)
#     l.sort()
#     # print(l)
#     l, indexes = zip(*l)
#     # print(l, indexes)
#     for i in range(n-2):
#         remaining = target - l[i]
#         # print(l[i], ",  remaining:" , remaining)
#         if remaining<=0:
#             print("IMPOSSIBLE")
#             exit()



#         c1 = max(bisect_left(l, remaining//2, lo=i+1) -1, i+1)
#         c2 = c1+1
#         # c1 = i+1
#         # c2 = n-1
#         while True:
#             # print(c1, c2)

#             lc1 = l[c1]
#             lc2 = l[c2]
#             val = l[i]+lc1+lc2
#             if val == target:
#                 # print(l[i], lc1, lc2)
#                 print(indexes[i], indexes[c1], indexes[c2])
#                 exit()
#             elif val < target:
#                 c2+=1
#                 if c2==n:
#                     break
#             else :
#                 c1-=1
#                 if c1==i:
#                     break
#     print("IMPOSSIBLE")

# main()


import sys
from bisect import bisect_left
def main():
    data = sys.stdin.buffer.read().split()
    n, target = int(data[0]), int(data[1])
    if target<=2:
        print("IMPOSSIBLE")
        exit()

    l = list(zip(list(map(int, data[2:])), range(1,n+1)))
    # print(l)
    l.sort()
    # print(l)
    l, indexes = zip(*l)
    # print(l, indexes)
    for i in range(n-2):
        remaining = target - l[i]
        # print(l[i], ",  remaining:" , remaining)
        if remaining<=0:
            print("IMPOSSIBLE")
            exit()


        c1 = i+1
        c2 = n-1
        while True:
            # print(c1, c2)

            lc1 = l[c1]
            lc2 = l[c2]
            val = l[i]+lc1+lc2
            if val == target:
                print(indexes[i], indexes[c1], indexes[c2])
                exit()
            elif val < target:
                c1+=1
            else :
                c2-=1
            if c1 == c2:
                break
    print("IMPOSSIBLE")

main()

Test details

Test 1

Verdict: ACCEPTED

input
`1 3 1` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 2

Verdict: ACCEPTED

input
`3 5 1 3 2` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 3

Verdict: ACCEPTED

input
`3 6 1 3 2` view save

correct output
`1 3 2` view save

user output
`1 3 2` view save

Test 4

Verdict: ACCEPTED

input
`3 7 3 2 1` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 5

Verdict: ACCEPTED

input
`7 3 2 1 1 2 2 1 1` view save

correct output
`2 3 7` view save

user output
`2 3 7` view save

Test 6

Verdict: ACCEPTED

input
`7 4 1 1 2 2 1 2 1` view save

correct output
`1 2 6` view save

user output
`1 2 6` view save

Test 7

Verdict: ACCEPTED

input
`7 5 1 2 1 2 2 1 1` view save

correct output
`1 2 5` view save

user output
`1 2 5` view save

Test 8

Verdict: ACCEPTED

input
`7 6 2 1 1 1 1 2 2` view save

correct output
`1 6 7` view save

user output
`1 6 7` view save

Test 9

Verdict: ACCEPTED

input
`5000 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...` view save

correct output
`1 2 5000` view save

user output
`1 2 5000` view save

Test 10

Verdict: ACCEPTED

input
`5000 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 11

Verdict: ACCEPTED

input
`5000 6 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...` view save

correct output
`714 3518 4240` view save

user output
`714 3518 4240` view save

Test 12

Verdict: ACCEPTED

input
`5000 919900245 663612758 9075403 585385629 98...` view save

correct output
`2787 465 2266` view save

user output
`2787 465 2266` view save

Test 13

Verdict: ACCEPTED

input
`5000 999989608 12983 25966 38949 51932 64915 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 14

Verdict: ACCEPTED

input
`5000 1000000000 65536 131072 196608 262144 327...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 15

Verdict: ACCEPTED

input
`5000 642700000 6427 12854 19281 25708 32135 3...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 16

Verdict: ACCEPTED

input
`5000 919900246 663612758 9075403 585385629 98...` view save

correct output
`193 1698 4019` view save

user output
`193 1698 4019` view save

Test 17

Verdict: ACCEPTED

input
`5000 919900247 663612758 9075403 585385629 98...` view save

correct output
`4258 470 1911` view save

user output
`4258 470 1911` view save

Test 18

Verdict: ACCEPTED

input
`5000 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 ...` view save

correct output
`4998 4999 5000` view save

user output
`4998 4999 5000` view save

Test 19

Verdict: ACCEPTED

input
`5000 919900247 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 20

Verdict: ACCEPTED

input
`4999 919900245 9075403 585385629 987230075 83...` view save

correct output
`2786 464 2265` view save

user output
`2786 464 2265` view save

Test 21

Verdict: ACCEPTED

input
`5000 1000000000 261323261 25262018 237798562 3...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 22

Verdict: ACCEPTED

input
`5000 76305003 1 5088 10175 15262 20349 25436...` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Test 23

Verdict: ACCEPTED

input
`2 6 2 2` view save

correct output
`IMPOSSIBLE` view save

user output
`IMPOSSIBLE` view save

Aalto Competitive Programming 2026 - wk7 - Mon

3SUM

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Tasks

Submissions (aalto26gm_007)