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# 11.17 (Financial tsunami) Banks lend money to each other. In tough economic times,
# if a bank goes bankrupt, it may not be able to pay back the loan. A bank’s total
# assets are its current balance plus its loans to other banks. The diagram in
# Figure 11.9 shows five banks. The banks’ current balances are 25, 125, 175,
# 75, and 181 million dollars, respectively. The directed edge from node 1 to
# node 2 indicates that bank 1 lends 40 million dollars to bank 2.
# If a bank’s total assets are under a certain limit, the bank is unsafe. The money
# it borrowed cannot be returned to the lender, and the lender cannot count the
# loan in its total assets. Consequently, the lender may also be unsafe if its total
# assets are under the limit. Write a program to find all unsafe banks. Your program
# should read the input as follows. It first reads two integers n and limit,
# where n indicates the number of banks and limit is the minimum total assets
# for keeping a bank safe. It then reads n lines that describe the information for n
# banks with ids from 0 to n - 1. The first number in the line is the bank’s
# balance, the second number indicates the number of banks that borrowed
# money from the bank, and the rest are pairs of two numbers. Each pair
# describes a borrower. The first number in the pair is the borrower’s id and the
# second is the amount borrowed. For example, the input for the five banks in
# Figure 11.9 is as follows (note that the limit is 201):
# 5 201
# 25 2 1 100.5 4 320.5
# 125 2 2 40 3 85
# 175 2 0 125 3 75
# 75 1 0 125
# 181 1 2 125
# The total assets of bank 3 are (75 + 125), which is under 201, so bank 3 is
# unsafe. After bank 3 becomes unsafe, the total assets of bank 1 fall below the limit
# (125 + 40), so bank 1 also becomes unsafe. The output of the program should be:
# Unsafe banks are 3 1
# (Hint: Use a two-dimensional list borrowers to represent loans.
# borrowers[i][j] indicates the loan that bank i loans to bank j. Once bank j
# becomes unsafe, borrowers[i][j] should be set to 0.)
n, limit = eval(input("Enter number of banks and limit: "))
borrowers = []
for i in range(n):
lst = [0] * n
borrowers.append(lst) # first index for the balance and the rest for borrowed loans
for i in range(n):
line = input().split()
borrowers[i][i] = eval(line[0])
num_of_borrowers = int(line[1])
for b in range(num_of_borrowers):
id = int(line[b * 2 + 2])
loan = eval(line[b * 2 + 3])
borrowers[i][id] = loan
unsafe = []
assets = [0] * n
# computing total assets for each bank
for bank in borrowers:
id = borrowers.index(bank)
balance = bank[id]
assets[id] = sum(bank)
if (assets[id]) < limit:
unsafe.append(id)
# it affects other banks, i.e each bank lent money to unsafe bank, its total assets fall
# with the amount lent to an unsafe bank
for x in range(len(borrowers)):
if borrowers[id] == borrowers[x]:
continue
borrowers[x][id] = 0
if sum(borrowers[x]) < limit:
unsafe.append(borrowers.index(borrowers[x]))
print("Unsafe banks are", " ".join(str(x) for x in unsafe))
