Buggy python submission (verdict: Time Limit Exceeded):
def main():
    import sys 
    input = sys.stdin.readline
    n = int(input())
    l = list(map(int,input().split()))
    c1 = [0]*60
    c0 = [0]*60
    mod = 10**9+7

    for i in l:
        for j in range(60):
            if (i >> j) & 1:
                c1[j] += 1
            else:
                c0[j] += 1

    ans = 0
    ni = 1
    for i in range(60):
        ans += (c1[i]*c0[i]*ni)%mod
        ans %= mod
        ni = ni*2%mod
    print(ans%mod)
if __name__ == "__main__":
    main()


Fixed submission:
def main():
    import sys 
    input = sys.stdin.readline
    n = int(input())
    l = list(map(int,input().split()))
    c1 = [0]*60
    c0 = [0]*60
    mod = 10**9+7

    for i in l:
        for j in range(60):
            if (i >> j) & 1:
                c1[j] += 1
            else:
                c0[j] += 1

    ans = 0
    ni = 1
    for i in range(60):
        ans += (c1[i]*c0[i]*ni)%mod
        ans %= mod
        ni = ni*2%mod
    print(ans%mod)
if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
l = list(map(int,input().split()))
c1 = [0]*70
c0 = [0]*70
mod = 10**9+7

for i in l:
    for j in range(60):
        if (i >> j) & 1:
            c1[j] += 1
        else:
            c0[j] += 1

ans = 0
ni = 1
for i in range(70):
    ans += (c1[i]*c0[i]*ni)%mod
    ans %= mod
    ni = ni*2%mod
print(ans%mod)


Fixed submission:
def main():
    import sys 
    input = sys.stdin.readline
    n = int(input())
    l = list(map(int,input().split()))
    c1 = [0]*60
    c0 = [0]*60
    mod = 10**9+7

    for i in l:
        for j in range(60):
            if (i >> j) & 1:
                c1[j] += 1
            else:
                c0[j] += 1

    ans = 0
    ni = 1
    for i in range(60):
        ans += (c1[i]*c0[i]*ni)%mod
        ans %= mod
        ni = ni*2%mod
    print(ans%mod)
if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
l = list(map(int,input().split()))
count = 0
mod = 10**9+7
for i in range(n-1):
  for j in range(i+1,n):
    count = count + (l[i]^l[j])%mod
print(count%mod)
  


Fixed submission:
def main():
    import sys 
    input = sys.stdin.readline
    n = int(input())
    l = list(map(int,input().split()))
    c1 = [0]*60
    c0 = [0]*60
    mod = 10**9+7

    for i in l:
        for j in range(60):
            if (i >> j) & 1:
                c1[j] += 1
            else:
                c0[j] += 1

    ans = 0
    ni = 1
    for i in range(60):
        ans += (c1[i]*c0[i]*ni)%mod
        ans %= mod
        ni = ni*2%mod
    print(ans%mod)
if __name__ == "__main__":
    main()

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
l = list(map(int,input().split()))
count = 0
mod = 10**9+7
for i in range(n-1):
  for j in range(i,n):
    count = count + (l[i]^l[j])%mod
print(count%mod)
  

Fixed submission:
def main():
    import sys 
    input = sys.stdin.readline
    n = int(input())
    l = list(map(int,input().split()))
    c1 = [0]*60
    c0 = [0]*60
    mod = 10**9+7

    for i in l:
        for j in range(60):
            if (i >> j) & 1:
                c1[j] += 1
            else:
                c0[j] += 1

    ans = 0
    ni = 1
    for i in range(60):
        ans += (c1[i]*c0[i]*ni)%mod
        ans %= mod
        ni = ni*2%mod
    print(ans%mod)
if __name__ == "__main__":
    main()