942. DI String Match #

题目 #

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".

题目大意 #

给定只含 “I”（增大）或 “D”（减小）的字符串 S ，令 N = S.length。返回 [0, 1, …, N] 的任意排列 A 使得对于所有 i = 0, …, N-1，都有：

• 如果 S[i] == “I”，那么 A[i] < A[i+1]
• 如果 S[i] == “D”，那么 A[i] > A[i+1]

解题思路 #

• 给出一个字符串，字符串中只有字符 "I" 和字符 "D"。字符 "I" 代表 A[i] < A[i+1]，字符 "D" 代表 A[i] > A[i+1] ，要求找到满足条件的任意组合。
• 这一题也是水题，取出字符串长度即是最大数的数值，然后按照题意一次排出最终数组即可。

代码 #

package leetcode

func diStringMatch(S string) []int {
	result, maxNum, minNum, index := make([]int, len(S)+1), len(S), 0, 0
	for _, ch := range S {
		if ch == 'I' {
			result[index] = minNum
			minNum++
		} else {
			result[index] = maxNum
			maxNum--
		}
		index++
	}
	result[index] = minNum
	return result
}