Fever Chart

**Problem.** Line 1: n q. Line 2: n initial values. Then q ops: "1 l r v" adds v on [l, r]; "2 l r" prints the sum of [l, r]. **Constraints:** 1 <= n, q <= 200000; |values|, |v| <= 1e4; sums fit in 64 bits. **R versus W.** The graded wrong solution applies each add tag without multiplying by the segment length — every add lands short. Target: full solve within 40 minutes.