End-to-End Debugger Simulation | Dataford Interview Questions

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Problem

For an HRT-style debugging trace, a program has executable lines numbered from 1 through total_lines. The debugger starts stopped at line 1. Given sorted breakpoint locations and a sequence of commands, simulate execution and return the final line where the debugger stops.

A next command advances execution by exactly one line. A continue command advances to the first breakpoint strictly greater than the current line. If no such breakpoint exists, it advances directly to total_lines. Once the debugger reaches total_lines, all later commands leave it there.

Breakpoints are unique and sorted in strictly increasing order.

Formal Specification

Implement final_debug_line(total_lines, breakpoints, actions):

total_lines: integer, the last executable line.
breakpoints: sorted list of integers identifying breakpoint lines.
actions: list containing only the strings "next" and "continue".
Return the final stopped line as an integer.

Constraints

1 <= total_lines <= 10^9
0 <= len(breakpoints) <= 10^6
0 <= len(actions) <= 10^6
1 <= breakpoints[i] <= total_lines
Breakpoints are strictly increasing
actions contains only "next" and "continue"

Function Signature

def final_debug_line(total_lines, breakpoints, actions):