Number of Good Ways to Split a String
给一个字符串s, 求有多少种分割方法, 让分割的两个字符串的不同字符数量相同.
class Solution {
public int numSplits(String s) {
int res = 0;
Map<Character, Integer> map = new HashMap<>();
for(char c : s.toCharArray())
map.put(c, map.getOrDefault(c, 0) + 1);
Map<Character, Integer> left = new HashMap<>();
for(char c : s.toCharArray()){
left.put(c, left.getOrDefault(c, 0) + 1);
map.put(c, map.get(c) - 1);
if(map.get(c) == 0)
map.remove(c);
if(map.size() == left.size())
res++;
}
return res;
}
}