[1 6 9 4 6 9 7 6 4 4 9 8 7]

[1 → 6 → 9 ← 4 6 → 9 ← 7 ← 6 ← 4 4 → 9 ← 8 ← 7]

[20 32 28]

Input  => [10 15 20 10 20 10 10]
          [10 → 15 → 20 10 20 ← 10 10]
Output => [45 10 30 10]

Input  => [9 9 9 9 8 1 8]
          [9 9 9 9 ← 8 1 8]
Output => [9 9 9 17 1 8]

Input  => [1 6 9 4 6 9 7 6 4 4 9 8 7]
          [1 → 6 → 9 ← 4 6 → 9 ← 7 ← 6 ← 4 4 → 9 ← 8 ← 7]
Output => [20 32 28]