GuilinDev

Lc0161

05 August 2008

161 One Edit Distance

做一次插入/删除/取代的edit,判断两个string是否相等

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/*
 * There're 3 possibilities to satisfy one edit distance apart: 
 * 
 * 1) Replace 1 char:
 	  s: a B c
 	  t: a D c
 * 2) Delete 1 char from s: 
	  s: a D  b c
	  t: a    b c
 * 3) Delete 1 char from t
	  s: a   b c
	  t: a D b c
 */
public boolean isOneEditDistance(String s, String t) {
    for (int i = 0; i < Math.min(s.length(), t.length()); i++) { 
    	if (s.charAt(i) != t.charAt(i)) {
    		if (s.length() == t.length()) // s has the same length as t, so the only possibility is replacing one char in s and t
    			return s.substring(i + 1).equals(t.substring(i + 1));
			else if (s.length() < t.length()) // t is longer than s, so the only possibility is deleting one char from t
				return s.substring(i).equals(t.substring(i + 1));	        	
			else // s is longer than t, so the only possibility is deleting one char from s
				return t.substring(i).equals(s.substring(i + 1));
    	}
    }       
    //All previous chars are the same, the only possibility is deleting the end char in the longer one of s and t 
    return Math.abs(s.length() - t.length()) == 1;        
}