37 lines
597 B
Go
37 lines
597 B
Go
// Package q42 implements a solution for https://leetcode.com/problems/trapping-rain-water/
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package q42
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func trap(height []int) int {
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water := 0
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mid := 0
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// From left
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maxHeight, stash := 0, 0
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for i, h := range height {
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if h >= maxHeight {
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maxHeight = h
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water += stash
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stash = 0
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mid = i
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} else {
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stash += maxHeight - h
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}
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}
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// From right
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maxHeight, stash = 0, 0
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for i := len(height) - 1; i >= mid; i-- {
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h := height[i]
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if h >= maxHeight {
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maxHeight = h
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water += stash
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stash = 0
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} else {
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stash += maxHeight - h
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}
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}
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return water
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}
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var _ = trap
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