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Concept

Variable-Size Window

The expand → repair → record template
step 1 / 24
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Concept
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1// the variable-window template
2l ← 0; best ← 0
3for r ← 0 to n − 1:
4    window absorbs arr[r]          // expand
5    while invariant broken:        // here: sum ≤ 8
6        window drops arr[l]; l++   // contract
7    best = max(best, r − l + 1)    // record
8return best
state
  • n7

line 1Fixed windows slide; VARIABLE windows breathe. R always moves right absorbing elements; L moves right only to FIX the window when a rule breaks. That rule is called the INVARIANT.