Problem: Given is a string S of length N-1. Each character in S is `<` or `>`.  A sequence of N non-negative integers, a_1,a_2,\cdots,a_N, is said to be _good_ when the following condition is satisfied for all i (1 \leq i \leq N-1):    * If S_i= `<`: a_i<a_{i+1}   * If S_i= `>`: a_i>a_{i+1}  Find the minimum possible sum of the elements of a good sequence of N non- negative integers.

Submission attempts (in order):
S = input()
S_length = len(S)
k = 1
s_l=[]
for i in range(S_length-1):
  s_x=S[i]
  if S[i+1]==s_x:
    k+=1
  else:
    s_l.append(s_x*k)
    k=1

if s_l[-1][0]!=S[-1]:
  s_l.append(S[-1])
  
        
        
def n_sum(n):
  return n*(n+1)//2
        

s_l_length = len(s_l)
answer=0
if s_l[0][0]=='<':
  if s_l_length%2==0:
    for i in range(0,s_l_length,2):
      s_1=s_l[i]
      s_2=s_l[i+1]
      s_1_l=len(s_1)
      s_2_l=len(s_2)
      if s_1_l<=s_2_l:
        answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
      else:
        answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  else:
    for i in range(0,s_l_length,2):
      if i==s_l_length-1:
        answer+=n_sum(len(s_l[i]))
      else:
        s_1=s_l[i]
        s_2=s_l[i+1]
        s_1_l=len(s_1)
        s_2_l=len(s_2)
        if s_1_l<=s_2_l:
          answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
        else:
          answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
          
else:
  answer+=n_sum(len(s_l.pop(0)))
  s_l_length-=1
  if s_l_length%2==0:
    for i in range(0,s_l_length,2):
      s_1=s_l[i]
      s_2=s_l[i+1]
      s_1_l=len(s_1)
      s_2_l=len(s_2)
      if s_1_l<=s_2_l:
        answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
      else:
        answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  else:
    for i in range(0,s_l_length,2):
      if i==s_l_length-1:
        answer+=n_sum(len(s_l[i]))
      else:
        s_1=s_l[i]
        s_2=s_l[i+1]
        s_1_l=len(s_1)
        s_2_l=len(s_2)
        if s_1_l<=s_2_l:
          answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
        else:
          answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  
      
print(answer)

S = input()
from itertools import groupby
S_length = len(S)
k = 1
s_l=[k*len(list(g)) for k, g in groupby(S)]
  
        
        
def n_sum(n):
  return n*(n+1)//2
        

s_l_length = len(s_l)
answer=0
if s_l[0][0]=='<':
  if s_l_length%2==0:
    for i in range(0,s_l_length,2):
      s_1=s_l[i]
      s_2=s_l[i+1]
      s_1_l=len(s_1)
      s_2_l=len(s_2)
      if s_1_l<=s_2_l:
        answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
      else:
        answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  else:
    for i in range(0,s_l_length,2):
      if i==s_l_length-1:
        answer+=n_sum(len(s_l[i]))
      else:
        s_1=s_l[i]
        s_2=s_l[i+1]
        s_1_l=len(s_1)
        s_2_l=len(s_2)
        if s_1_l<=s_2_l:
          answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
        else:
          answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
          
else:
  answer+=n_sum(len(s_l.pop(0)))
  s_l_length-=1
  if s_l_length%2==0:
    for i in range(0,s_l_length,2):
      s_1=s_l[i]
      s_2=s_l[i+1]
      s_1_l=len(s_1)
      s_2_l=len(s_2)
      if s_1_l<=s_2_l:
        answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
      else:
        answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  else:
    for i in range(0,s_l_length,2):
      if i==s_l_length-1:
        answer+=n_sum(len(s_l[i]))
      else:
        s_1=s_l[i]
        s_2=s_l[i+1]
        s_1_l=len(s_1)
        s_2_l=len(s_2)
        if s_1_l<=s_2_l:
          answer+=n_sum(s_1_l-1)+n_sum(s_2_l)
        else:
          answer+=n_sum(s_1_l)+n_sum(s_2_l-1)
  
      
print(answer)

Verdicts: Runtime Error

Accepted