Problem p02774 (python)

Fixed submission:
N,K = map(int,input().split())
A = list(map(int,input().split()))
A = sorted(A)
mi = 0
zero = 0
for a in A:
  if a<0:
    mi+=1
  elif a==0:
    zero+=1
  else:
    break

plu = N-mi-zero
A_mi = A[0:mi:]
A_mi_rev = A_mi[::-1]
A_plu = A[mi+zero::]
A_plu_rev = A_plu[::-1]
num_mi = plu*mi
num_zero = (plu+mi)*zero+(zero*(zero-1))//2
r = max(A[-1]**2+10,A[0]**2+10)
l = A[0]*A[-1]-10
while l+1!=r:
  m = (l+r)//2
  num = 0
  if m>0:
    num+=num_mi+num_zero
    if num>=K:
      r=m
      continue
    cou=0
    for i in range(0,plu):
      while True:
        if cou>=plu-i-1:
          num+=plu-i-1
          break
        x = A_plu_rev[i]*A_plu[cou]
        if x<m:
          cou+=1
        else:
          num+=cou
          break
          
      if num>=K:
        break
    if num>=K:
      r=m
      continue
    cou = 0
    for i in range(0,mi):
      while True:
        if cou>=mi-i-1:
          num+=mi-i-1
          break
        x = A_mi[i]*A_mi_rev[cou]
        if x<m:
          cou+=1
        else:
          num+=cou
          break
          
      if num>=K:
        break

    if num>=K:
      r=m
    else:
      l=m
    
  elif m==0:
    num+=num_mi
    if num>=K:
      r=m
    else:
      l=m
  else:
    cou = 0
    for a in A_mi_rev:
      while True:
        if cou==plu:
          num+=cou
          break
        x = a*A_plu_rev[cou]
        if x<m:
          cou+=1
        else:
          num+=cou
          break
          
      if num>=K:
        break
    if num>=K:
      r = m
    else:
      l = m
      
print(l)

Buggy submission (verdict: Runtime Error):
N,K = map(int,input().split())
A = list(map(int,input().split()))
A = sorted(A)
mi = 0
zero = 0
for a in A:
  if a<0:
    mi+=1
  elif a==0:
    zero+=1
  else:
    break

plu = N-mi-zero
A_mi = A[0:mi:]
A_mi_rev = A_mi[::-1]
A_plu = A[mi+zero::]
A_plu_rev = A_plu[::-1]
num_mi = plu*mi
num_zero = (plu+mi)*zero+(zero*(zero-1))//2
print(A_mi[0]*A_mi[1])

Buggy submission (verdict: Runtime Error):
N,K = map(int,input().split())
A = list(map(int,input().split()))
A = sorted(A)
mi = 0
zero = 0
for a in A:
  if a<0:
    mi+=1
  elif a==0:
    zero+=1
  else:
    break

plu = N-mi-zero
A_mi = A[0:mi:]
A_mi_rev = A_mi[::-1]
A_plu = A[mi+zero::]
A_plu_rev = A_plu[::-1]
num_mi = plu*mi
num_zero = (plu+mi)*zero+(zero*(zero-1))//2
print(A_plu_rev[0]*A_plu_rev[1])

Buggy submission (verdict: Runtime Error):
N,K = map(int,input().split())
A = list(map(int,input().split()))
A = sorted(A)
mi = 0
zero = 0
for a in A:
  if a<0:
    mi+=1
  elif a==0:
    zero+=1
  else:
    break

plu = N-mi-zero
A_mi = A[0:mi:]
A_mi_rev = A_mi[::-1]
A_plu = A[mi+zero::]
A_plu_rev = A_plu[::-1]
num_mi = plu*mi
num_zero = (plu+mi)*zero+(zero*(zero-1))//2
r = A[-1]**2+1
l = A[0]*A[-1]-1
while l+1!=r:
  m = (l+r)//2
  num = 0
  if m>0:
    num+=num_mi+num_zero
    if num>=K:
      r=m
      continue
    cou=0
    for i in range(0,plu-1):
      j = max(i+1,cou)
      while True:
        if j==plu:
          cou=j
          num+=j-i-1
          break
        x = A_plu_rev[i]*A_plu_rev[j]
        if x<m:
          j+=1
        else:
          cou=j-1
          num+=j-i-1
          break
      if num>=K:
        break
    if num>=K:
      r=m
      continue
    for i in range(0,mi-1):
      j = max(i+1,cou)
      while True:
        if j==mi:
          cou=j
          num+=j-i-1
          break
        x = A_mi[i]*A_mi[j]
        if x<m:
          j+=1
        else:
          cou=j-1
          num+=j-i-1
          break
      if num>=K:
        break
        
    if num>=K:
      r=m
    else:
      l=m
      
  elif m==0:
    num+=num_mi
    if num>=K:
      r=m
    else:
      l=m
  else:
    b = plu
    cou = 0
    for a in A_mi_rev:
      while True:
        if cou==b:
          num+=cou
          break
        x = a*A_plu_rev[cou]
        if x<m:
          cou+=1
        else:
          num+=cou
          break
          
      if num>=K:
        break
    if num>=K:
      r = m
    else:
      l = m
      
print(l)