Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
for i in range(N):
    for j in range(i+1, N):
        if Asum[i] == Adif[j]:
            ans += 1

print(ans)


Fixed submission:
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
d = defaultdict(int)
for i in range(N):
    ans += d[Adif[i]]
    d[Asum[i]] += 1

print(ans)

Buggy python submission (verdict: Runtime Error):
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
input = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
for i in range(N):
    for j in range(i+1, N):
        if Asum[i] == Adif[j]:
            ans += 1

print(ans)


Fixed submission:
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
d = defaultdict(int)
for i in range(N):
    ans += d[Adif[i]]
    d[Asum[i]] += 1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# input = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
for i in range(N):
    for j in range(i+1, N):
        if Asum[i] == Adif[j]:
            ans += 1

print(ans)


Fixed submission:
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
d = defaultdict(int)
for i in range(N):
    ans += d[Adif[i]]
    d[Asum[i]] += 1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = []
Adif = []
for i, j in enumerate(A):
    Asum.append(i+j)
    Adif.append(i-j)

ans = 0
for i in range(N):
    for j in range(i+1, N):
        if Asum[i] == Adif[j]:
            ans += 1

print(ans)


Fixed submission:
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
d = defaultdict(int)
for i in range(N):
    ans += d[Adif[i]]
    d[Asum[i]] += 1

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = []
Adif = []
for i, j in enumerate(A):
    Asum.append(i+j)
    Adif.append(i-j)

ans = 0
for i in range(N):
    for j in range(i+1, N):
        if Asum[i] == Adif[j]:
            ans += 1

print(ans)


Fixed submission:
from collections import defaultdict
from math import gcd
import time
import sys
from collections import Counter
import itertools
import math
# read = sys.stdin.buffer.read
# readline = sys.stdin.buffer.readline
# readlines = sys.stdin.buffer.readlines
input = sys.stdin.readline

start = time.time()
N = int(input())
A = list(map(int, input().split(' ')))
Asum = [i+A[i] for i in range(N)]
Adif = [i-A[i] for i in range(N)]

ans = 0
d = defaultdict(int)
for i in range(N):
    ans += d[Adif[i]]
    d[Asum[i]] += 1

print(ans)