763. Partition Labels

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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.

Approach #1: C++.

class Solution {
public:
    vector<int> partitionLabels(string S) {
        int len = S.length();
        int curLen = 0;
        vector<int> ans;
        
        for (int i = 0; i < len; ++i) {
            curLen = helper(S, i);
            for (int j = i+1; j < curLen; ++j) {
                curLen = max(curLen, helper(S, j));
            }
            
            ans.push_back(curLen-i+1);
            i = curLen;
        }
        
        return ans;
    }
    
    int helper(string S, int index) {
        int curLen = index;
        int len = S.length();
        int temp;
        while (index >= 0) {
            curLen = index;
            index = S.find(S[curLen], curLen+1);
        }
        
        return curLen;
    }
};

Analysis:

I use helper function to find the last index of current character. In the partitionLabels function we traversing the string and find the min interval.

763. Partition Labels

标签：abc   nat   char   man   put   hat   list   ret   cad   

原文地址：https://www.cnblogs.com/ruruozhenhao/p/10252376.html