Largest Merge Of Two Strings
A medium-tier problem at 51% community acceptance, tagged with Two Pointers, String, Greedy. Reported in interviews at Snap and 0 others.
Largest Merge Of Two Strings is a greedy two-pointer problem that Snap asks often enough to show up in real OAs. The acceptance rate sits at 51%, which tells you most people miss the optimal strategy on first sight. The trick isn't just merging two strings; it's figuring out which character to pick at each step to produce the lexicographically largest result. You need to know when the obvious choice fails and when to look ahead. If this problem hits your live assessment and you blank on the pattern, StealthCoder solves it in seconds, invisible to the proctor.
Companies that ask "Largest Merge Of Two Strings"
Largest Merge Of Two Strings is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Built by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share.
Get StealthCoderThe greedy approach seems straightforward: at each step, pick the character from whichever string has the larger next character. But that fails because a string with a smaller immediate character might have much larger characters downstream. The real solution compares not just the next character, but the remainder of both strings from that point. You use two pointers, one per string, and at each step compare the substring starting from the current pointer position in string one against the substring from the current pointer in string two. Pick whichever one is lexicographically larger, consume that character, and advance that pointer. This two-pointer greedy strategy with lookahead is where most candidates stumble. StealthCoder handles the comparison logic and pointer management so you don't second-guess yourself during the live OA.
Pattern tags
You know the problem.
Make sure you actually pass it.
Largest Merge Of Two Strings recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Built by an engineer at a top-10 tech company who can solve these problems cold but didn't want to trust himself in a 90-minute screen share. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Largest Merge Of Two Strings interview FAQ
Why does picking the larger immediate character not work?+
Because a string starting with 'a' might continue 'zzz' while the alternative starts 'b' and then becomes much smaller. You have to compare the full remaining strings lexicographically, not just the next single character. That's where greedy with lookahead comes in.
Is this really only asked at Snap?+
The input data shows one company reporting it. That doesn't mean others won't ask it. Similar two-pointer greedy problems appear across companies. This pattern is worth knowing even if you're not interviewing at Snap.
What's the time complexity and does it matter?+
Comparing remainders at each step can be expensive. Naive comparison is O(n*m^2) for strings of length n and m. Optimized versions use rolling hashes or clever substring tricks to bring it closer to O(n*m). In a live OA, start with the clear solution first.
How does this relate to Two Pointers and Greedy?+
Two pointers let you traverse both strings simultaneously without redundant passes. Greedy means you commit to a choice at each step without backtracking. Together they give you the lexicographically largest merge in linear to near-linear time.
Should I drill this before an OA?+
At 51% acceptance, it's middle-tier difficulty. If you're interviewing at Snap or doing general string prep, yes. If not, it's lower priority unless you're blocking on greedy logic across multiple problems.
Want the actual problem statement? View "Largest Merge Of Two Strings" on LeetCode →