Fix Bootloader Program by Swapping One Instruction to Avoid Loop

Problem: Fix a Bootloader Program by Swapping One Instruction You are given a line-by-line instruction file (program). Each line contains an instruction and an integer value. The program starts at line 0 and maintains a global accumulator acc, initially 0. Supported instructions: plus x: set acc += x, then execute the next line (pc += 1). next x: do not modify acc, execute the next line (pc += 1). The parameter x has no effect. jump x: do not modify acc, jump to line pc + x (pc += x). Termination rules: Normal termination: when the program counter pc becomes len(program) (i.e., just past the last line), terminate and return acc. Loop detection: if an instruction is about to be executed for the second time (i.e., pc lands on a previously visited line), the program is considered stuck in an infinite loop. It is known that exactly one line is wrong: on that line, jump and next were swapped (so a line that should be jump is written as next, or vice versa). plus is always correct. Your task is to swap exactly one jump/next (keeping its integer parameter unchanged) so that the program terminates normally. Output the value of acc after the fixed program terminates. Input Format Read from stdin: Line 1: integer n, number of instructions. Next n lines: op value, where op is plus / next / jump, and value is a signed integer such as +3, -10, or 0. Output Format Print a single integer: acc after the fixed program terminates. Constraints 1 <= n <= 200000 value fits in 32-bit signed integer There exists exactly one swap of a single jump/next that makes the program terminate normally Example Input: 6 plus +1 next +2 jump +3 plus +3 jump -1 plus +2 Output (for format illustration only): 3 Example Input 6 plus +1 next +2 jump +3 plus +3 jump -1 plus +2 Output 3