A: problem-solving ideas
Time: The (n), Space: The (1)
Two: Complete code examples (C ++ version and the Java version)
C++:
class Solution { public: void reverseString(vector<char>& s) { int i = 0, j = s.size() - 1; for (; i < j; i++, j--) { swap(s[i],s[j]); } } };
Java:
class Solution { public void reverseString(char[] s) { int i=0,j=s.length-1; for(;i<j;i++,j--) { char temp=s[i]; s[i]=s[j]; s[j]=temp; } } }