leetcode.205.同构字符串(isomorphic-strings)

曾经终败给现在 2022-12-28 11:11 164阅读 0赞

# 同构字符串(isomorphic-strings) #

java  
[同构字符串(isomorphic-strings)][isomorphic-strings]  
[题解][Link 1]

package isomorphic_strings;
    
    import java.util.HashMap;
    
    public class Solution { 
    	
    public boolean isIsomorphic(String s, String t) { 
        int n = s.length();
        int[] mapS = new int[128];
        int[] mapT = new int[128];
        for (int i = 0; i < n; i++) { 
            char c1 = s.charAt(i);
            char c2 = t.charAt(i);
            //当前的映射值是否相同
            if (mapS[c1] != mapT[c2]) { 
                return false;
            } else { 
                //是否已经修改过，修改过就不需要再处理
                if (mapS[c1] == 0) { 
                    mapS[c1] = i + 1;
                    mapT[c2] = i + 1;
                }
            }
        }
        return true;
    }
        
        
        public boolean isIsomorphic2(String s, String t) { 
            return isIsomorphicHelper(s, t) && isIsomorphicHelper(t, s);
    
        }
    
        private boolean isIsomorphicHelper(String s, String t) { 
            int n = s.length();
            HashMap<Character, Character> map = new HashMap<>();
            for (int i = 0; i < n; i++) { 
                char c1 = s.charAt(i);
                char c2 = t.charAt(i);
                if (map.containsKey(c1)) { 
                    if (map.get(c1) != c2) { 
                        return false;
                    }
                } else { 
                    map.put(c1, c2);
                }
            }
            return true;
        }
        
        public static void main(String[] args) { 
    // System.out.println(new Solution().isIsomorphic("egg", "add"));
    		System.out.println(new Solution().isIsomorphic2("foo", "bar"));
    		System.out.println(new Solution().isIsomorphic2("ab", "cc"));
    	}
    }

[isomorphic-strings]: https://leetcode-cn.com/problems/isomorphic-strings
[Link 1]: https://leetcode-cn.com/problems/isomorphic-strings/solution/xiang-xi-tong-su-de-si-lu-fen-xi-duo-jie-fa-by-42/