{"blocks": [{"key": "8753a02b", "text": "Scenario", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "ffa6c1ee", "text": "An online payments company needs to build a system that detects fraudulent credit-card transactions in real time.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "9f94e6fb", "text": "Question", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "8f358fa0", "text": "Design a credit-card fraud-detection strategy. Describe data sources, feature engineering, model choices, real-time architecture, retraining cadence, and how you would monitor model drift.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "d1f30f88", "text": "Hints", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "ea229eed", "text": "Think supervised vs unsupervised methods, latency constraints, feedback loops, threshold tuning.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}], "entityMap": {}}