{"type":"excalidraw","version":2,"source":"https://AwesomeSystemDesign.dev","elements":[{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-1"}],"updated":0,"link":null,"locked":false,"id":"shape-0","type":"rectangle","seed":41,"x":30,"y":30,"width":477.7524400000001,"height":68,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-1"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-1","type":"text","seed":114,"x":50,"y":52.3,"width":437.7524400000001,"height":23.400000000000002,"fontSize":18,"fontFamily":1,"text":"Set Intersection: A.connections ∩ B.connections","originalText":"Set Intersection: A.connections ∩ B.connections","textAlign":"left","verticalAlign":"middle","containerId":"shape-0","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":1}},{"angle":0,"strokeColor":"#a68a53","backgroundColor":"#fff7e6","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-3"}],"updated":0,"link":null,"locked":false,"id":"shape-2","type":"rectangle","seed":187,"x":30,"y":123,"width":577.54084,"height":153,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-2"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-3","type":"text","seed":260,"x":50,"y":141,"width":537.54084,"height":117,"fontSize":18,"fontFamily":1,"text":"Approach 1: Real-Time Intersection\nLoad adjacency lists for A (500 IDs) and B (800 IDs)\nSorted arrays → merge-intersect in O(n+m)\n500 + 800 = 1,300 comparisons → microseconds\n✅ Works well when both lists fit in memory","originalText":"Approach 1: Real-Time Intersection\nLoad adjacency lists for A (500 IDs) and B (800 IDs)\nSorted arrays → merge-intersect in O(n+m)\n500 + 800 = 1,300 comparisons → microseconds\n✅ Works well when both lists fit in memory","textAlign":"left","verticalAlign":"middle","containerId":"shape-2","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":2}},{"angle":0,"strokeColor":"#9180ac","backgroundColor":"#f4effb","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-5"}],"updated":0,"link":null,"locked":false,"id":"shape-4","type":"rectangle","seed":333,"x":30,"y":301,"width":566.87512,"height":176.4,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-3"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-5","type":"text","seed":406,"x":50,"y":319,"width":526.87512,"height":140.4,"fontSize":18,"fontFamily":1,"text":"Approach 2: Pre-Computed (for very high fan-out users)\nCelebrities with 10M followers:\nReal-time intersect with 10M elements = too slow\nPre-compute top mutual connections offline\nStore: mutual:{A}:{B} → [user_ids] in cache\nTTL: 1 hour (connections don't change often)","originalText":"Approach 2: Pre-Computed (for very high fan-out users)\nCelebrities with 10M followers:\nReal-time intersect with 10M elements = too slow\nPre-compute top mutual connections offline\nStore: mutual:{A}:{B} → [user_ids] in cache\nTTL: 1 hour (connections don't change often)","textAlign":"left","verticalAlign":"middle","containerId":"shape-4","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":3}},{"angle":0,"strokeColor":"#6577aa","backgroundColor":"#eef1fc","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-7"}],"updated":0,"link":null,"locked":false,"id":"shape-6","type":"rectangle","seed":479,"x":30,"y":502.4,"width":548.25304,"height":199.8,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-4"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-7","type":"text","seed":552,"x":50,"y":520.4,"width":508.25304000000006,"height":163.8,"fontSize":18,"fontFamily":1,"text":"Approach 3: Bloom Filter Approximation\nFor \"mutual count\" (not exact list):\nBuild bloom filter of A's connections (compact, ~1 KB)\nCheck each of B's connections against bloom filter\nFalse positive rate ~1% → approximate count\nUse for display: \"~12 mutual connections\"\n✅ Constant memory regardless of connection count","originalText":"Approach 3: Bloom Filter Approximation\nFor \"mutual count\" (not exact list):\nBuild bloom filter of A's connections (compact, ~1 KB)\nCheck each of B's connections against bloom filter\nFalse positive rate ~1% → approximate count\nUse for display: \"~12 mutual connections\"\n✅ Constant memory regardless of connection count","textAlign":"left","verticalAlign":"middle","containerId":"shape-6","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":4}},{"angle":0,"strokeColor":"#628572","backgroundColor":"#edf5ee","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":[{"type":"text","id":"shape-9"}],"updated":0,"link":null,"locked":false,"id":"shape-8","type":"rectangle","seed":625,"x":30,"y":727.2,"width":618.20032,"height":82.80000000000001,"customData":{"revealStep":5}},{"angle":0,"strokeColor":"#394557","backgroundColor":"transparent","fillStyle":"solid","strokeWidth":1.5,"strokeStyle":"solid","roughness":0.7,"opacity":100,"version":1,"versionNonce":1,"isDeleted":false,"groupIds":["step-5"],"frameId":null,"roundness":null,"boundElements":null,"updated":0,"link":null,"locked":false,"id":"shape-9","type":"text","seed":698,"x":50,"y":745.2,"width":578.20032,"height":46.800000000000004,"fontSize":18,"fontFamily":1,"text":"Recommendation: Real-time intersect for normal users (< 10K)\nPre-computed for celebrities/influencers (> 10K connections)","originalText":"Recommendation: Real-time intersect for normal users (< 10K)\nPre-computed for celebrities/influencers (> 10K connections)","textAlign":"left","verticalAlign":"middle","containerId":"shape-8","lineHeight":1.3,"autoResize":false,"customData":{"revealStep":5}}],"appState":{"viewBackgroundColor":"#fbfbf8","gridSize":null},"files":{}}