# Leetcode: DI String Match

DI String Match Similar Problems:

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. 1 <= S.length <= 10000
2. S only contains characters “I” or “D”.

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

• Solution:
```// Blog link: https://code.dennyzhang.com/di-string-match
// Basic Ideas: two pointers
// Complexity: Time O(n), Space O(1)
func diStringMatch(S string) []int {
res := []int{}
i, j := 0, len(S)
for _, ch := range S {
if ch == 'I' {
res = append(res, i)
i++
} else {
res = append(res, j)
j--
}
}
res = append(res, i)
return res
}
```

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