Isomorphic Strings Problem & Solution
Given two strings s and t, determine if they are isomorphic.
Two strings s and t 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.
See the isomorphic strings problem on LeetCode.
C++ Solution
#pragma GCC optimize("Ofast")
#pragma GCC optimization("unroll-loops")
static const int _=[](){std::ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);return 0;}();
class Solution {
public:
bool isIsomorphic(string s, string t) {
unordered_map<char, char> map;
set<char> used;
for (int i = 0; i < s.size(); ++i) {
if (map.find(s[i]) == map.end() &&
used.find(t[i]) == used.end()) {
map[s[i]] = t[i];
used.insert(t[i]);
}
if (map[s[i]] != t[i]) {
return false;
}
}
return true;
}
};