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:
Swill have length in range[1, 500].Swill consist of lowercase letters ('a'to'z') only.
Runtime: 8 ms, faster than 43.40% of C++ online submissions for Partition Labels.
第一次实现用的是map，第二次实现用的是数组，差了一倍的运行速度。
#include <vector>
#include <string>
#include <unordered_map>
#include <map>
#include <iostream>
using namespace std;
class Solution {
public:
vector<int> partitionLabels(string S) {
int map[256];
for(int i=0; i<S.size(); i++){
map[(int)S[i]] = i;
}
int idx = 0;
vector<int> ret;
while(idx < S.size()){
int tmpidx = idx;
int maxback = map[(int)S[tmpidx]]+1;
while(tmpidx < S.size() && tmpidx < maxback){
maxback = max(maxback, map[(int)S[tmpidx]]+1);
tmpidx++;
}
ret.push_back(maxback - idx);
idx = maxback;
}
return ret;
}
};