Isomorphic Strings
Given two strings s and t, determine if they are isomorphic.
Two strings are isomorphic if the characters in s can be replaced to get t.
All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.
For example,
Given "egg"
, "add"
,
return true.
Given "foo"
, "bar"
,
return false.
Given "paper"
, "title"
,
return true.
Note:
You may assume both s and t have the same length.
两字符串有映射关系,即一一对应关系。
如egg,add.
e和a对应,g和d对应
刚开始用的map
class Solution {
public:
bool isIsomorphic(string s, string t) {
int n =s.length();
map<int,int>m1,m2;
for (int i = 0;i < n;i++) {
m1[s[i]] = t[i];
m2[t[i]] = s[i];
}
for (int i = 0;i < n;i++) {
if (m1[s[i]] != t[i]) return false;
if (m2[t[i]] != s[i]) return false;
}
return true;
}
};
后来想,用一个数组也一样,而且效率高了不少
class Solution {
public:
bool isIsomorphic(string s, string t) {
int n =s.length();
int m1[130] = {0},m2[130] = {0};
for (int i = 0;i < n;i++) {
m1[s[i]] = t[i];
m2[t[i]] = s[i];
}
for (int i = 0;i < n;i++) {
if (m1[s[i]] != t[i]) return false;
if (m2[t[i]] != s[i]) return false;
}
return true;
}
};