{"blocks": [{"key": "e288b924", "text": "Scenario", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "9734f479", "text": "You are building a travel-search engine that must 1) show customers the cheapest round-trip they can book if departure and return prices vary by day, and 2) generate all k-digit numbers that still look the same after a 180° rotation for fraud-detection image checks.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "0ae48fbb", "text": "Question", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "1f47daa4", "text": "Given two arrays, dep[i] = outbound ticket price on day i and ret[j] = return ticket price on day j, design an algorithm that returns the minimum possible total cost for any valid round-trip (depart before return). Analyze time and space complexity and discuss possible optimizations or alternative solutions. Given an integer k, generate all k-digit numbers that remain identical when rotated 180°. Provide an algorithm, analyze its complexity, and explain how your code handles corner cases.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "1b77b7c8", "text": "Hints", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "626fe360", "text": "Cheapest flight: pre-compute suffix minima or use two-pointer scan. Strobogrammatic: recurse from outer to inner, pairing digits {0,0},{1,1},{6,9},{8,8},{9,6}.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}], "entityMap": {}}