Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

public class Solution {
    public String reverseWords(String s) {
        char[] c = s.toCharArray();
        int pos = 0;
        for(int i=0;i<c.length;i++){
            if(c[i] == ' '){
                rev(c,pos,i-1);
                pos = i+1;
            }
        }
        rev(c,pos,c.length-1);
        return new String(c);
    }
    public void rev(char[] c, int start,int end){
        while(start<end){
            char tmp = c[start];
            c[start] = c[end];
            c[end] = tmp;
            start ++;
            end --;
        }
    }
}