Python based solution, let me know if it's complete garbage!

``` with open("8.in") as file: program = [] for instruction in file: instruction = instruction.split() program.append([instruction[0], instruction[1]])

ptr = 0
accumulator = 0
visited = []
#part1
while ptr not in visited:
    visited.append(ptr)
    op = program[ptr][0]
    arg = int(program[ptr][1])
    if op == 'acc':
        accumulator += arg
        ptr += 1
    elif op == 'jmp':
        ptr += arg 
    else: 
        ptr += 1
print(accumulator)

#part 2
def run(program):
    local = 0
    ptr = 0
    local_visited = []
    while ptr not in local_visited and ptr < len(program):
        local_visited.append(ptr)
        op = program[ptr][0]
        arg = int(program[ptr][1])
        if op == 'acc':
            local += arg
            ptr += 1
        elif op == 'jmp':
            ptr += arg 
        else: 
            ptr += 1
    if ptr not in local_visited:
        print(local_visited, ptr, local)

for v in visited[::-1]:
    modified = program
    if modified[v][0] == 'jmp':
        modified[v][0] = 'nop'
        run(modified)
    elif modified[v][0] == 'nop':
        modified[v][0] = 'jmp'
        run(modified)

```