50 lines
1.2 KiB
Go
50 lines
1.2 KiB
Go
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func threeSum(nums []int) (result [][]int) {
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target := 0
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sort.Ints(nums)
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for i := 0; i < len(nums)-2; i++ {
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// We don't want duplicates of the fixed value
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// which can cause duplicate triplets to appear.
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if i > 0 && nums[i] == nums[i-1] {
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continue
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}
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startPtr := i + 1
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endPtr := len(nums) - 1
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for startPtr < endPtr {
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sum := nums[i] + nums[startPtr] + nums[endPtr]
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if sum == target {
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result = append(
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result,
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[]int{nums[i], nums[startPtr], nums[endPtr]},
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)
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// Duplicate values can appear while scanning also. Presence of these
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// duplicate values can also result in duplicate triplets. So, for the
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// start and end pointers, we need to keep moving them until we are
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// clear of duplicates.
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for startPtr < endPtr && nums[startPtr] == nums[startPtr+1] {
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startPtr++
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}
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for endPtr > startPtr && nums[endPtr] == nums[endPtr-1] {
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endPtr--
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}
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// Since the loops above stop at the last duplicate value, we need to move
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// them by one step from both directions to continue with the logic.
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startPtr++
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endPtr--
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} else if sum < target {
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startPtr++
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} else {
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endPtr--
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}
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}
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}
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return
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}
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