algorithms/leetcode/math/diStringMatch.go at master · TTWShell/algorithms · GitHub

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/* https://leetcode.com/problems/di-string-match/description/
Given a string S that only contains "I" (increase) or "D" (decrease), let N = S.length.

Return any permutation A of [0, 1, ..., N] such that for all i = 0, ..., N-1:

If S[i] == "I", then A[i] < A[i+1]
If S[i] == "D", then A[i] > A[i+1]


Example 1:

	Input: "IDID"
	Output: [0,4,1,3,2]

Example 2:

	Input: "III"
	Output: [0,1,2,3]

Example 3:

	Input: "DDI"
	Output: [3,2,0,1]

Note:

	1 <= S.length <= 10000
	S only contains characters "I" or "D".
*/

package lmath

func diStringMatch(S string) []int {
	length := len(S)
	res := make([]int, length+1, length+1)
	I, D := 0, length
	for i := 0; i < length; i++ {
		if S[i] == 'I' {
			res[i] = I
			I++
		} else {
			res[i] = D
			D--
		}
	}
	res[length] = I
	return res
}