leetcode Weekly Contest 67 -- 763. Partition Labels

Description

A string S of lowercase letters is given. We want to partition this string into as many parts as possible so that each letter appears in at most one part, and return a list of integers representing the size of these parts.

Example 1:

Input: S = "ababcbacadefegdehijhklij"
Output: [9,7,8]
Explanation:
The partition is "ababcbaca", "defegde", "hijhklij".
This is a partition so that each letter appears in at most one part.
A partition like "ababcbacadefegde", "hijhklij" is incorrect, because it splits S into less parts.

Note:

1. S will have length in range [1, 500].
2. S will consist of lowercase letters ('a' to'z') only.

class Solution {
public:
vector<int> partitionLabels(string S) 
{
	int len = 0,m=0;
	vector<int>sum;
	map<char,int>mp;
	int i=0;

	while (i<S.length())
	{
		len++;
		for (; i < len; i++)
		{
			if (!mp.count(S[i]))
			{
				mp[S[i]] = 0;
				for (int j = S.length() - 1; j >= i; j--)
				{				
					if (S[i] == S[j])
					{
						if (len <= j)
							len = j + 1;
						break;
					}
				}
			}
		}
		sum.push_back(len - m);
		m = len;
	}
	return sum;
}
};