By now, you are given asecret signatureconsisting of character 'D' and 'I'. 'D' represents a decreasing relationship between two numbers, 'I' represents an increasing relationship between two numbers. And oursecret signaturewas constructed by a special integer array, which contains uniquely all the different number from 1 to n (n is the length of the secret signature plus 1). For example, the secret signature "DI" can be constructed by array [2,1,3] or [3,1,2], but won't be constructed by array [3,2,4] or [2,1,3,4], which are both illegal constructing special string that can't represent the "DI"secret signature.

On the other hand, now your job is to find the lexicographically smallest permutation of [1, 2, ... n] could refer to the givensecret signaturein the input.

Example 1:

Input:
 "I"

Output:
 [1,2]

Explanation:
 [1,2] is the only legal initial spectial string can construct secret signature "I", where the number 1 and 2 construct an increasing relationship.

Example 2:

Input:
 "DI"

Output:
 [2,1,3]

Explanation:
 Both [2,1,3] and [3,1,2] can construct the secret signature "DI", 


but since we want to find the one with the smallest lexicographical permutation, you need to output [2,1,3]

Note:

The input string will only contain the character 'D' and 'I'.

The length of input string is a positive integer and will not exceed 10,000

public class Solution {
    public int[] findPermutation(String s) {
        int[] res = new int[s.length() + 1];
        for (int i = 0; i < res.length; i++)
            res[i] = i + 1;
        int i = 1;
        while (i <= s.length()) {
            int j = i;
            while (i <= s.length() && s.charAt(i - 1) == 'D')
                i++;
            reverse(res, j - 1, i);
            i++;
        }
        return res;
    }
    public void reverse(int[] a, int start, int end) {
        for (int i = 0; i < (end - start) / 2; i++) {
            int temp = a[i + start];
            a[i + start] = a[end - i - 1];
            a[end - i - 1] = temp;
        }
    }
}