[LeetCode] 228. Summary Ranges 总结区间

Given a sorted integer array without duplicates, return the summary of its ranges.

Example 1:

Input:  [0,1,2,4,5,7]
Output: ["0->2","4->5","7"]
Explanation: 0,1,2 form a continuous range; 4,5 form a continuous range.

Example 2:

Input:  [0,2,3,4,6,8,9]
Output: ["0","2->4","6","8->9"]
Explanation: 2,3,4 form a continuous range; 8,9 form a continuous range.

Java:

class Solution {
    public List<String> summaryRanges(int[] nums) {
        List<String> list=new ArrayList();
        if(nums.length==1){
            list.add(nums[0]+"");
            return list;
        }
        for(int i=0;i<nums.length;i++){
            int a=nums[i];
            while(i+1<nums.length&&(nums[i+1]-nums[i])==1){
                i++;
            }
            if(a!=nums[i]){
                list.add(a+"->"+nums[i]);
            }else{
                list.add(a+"");
            }
        }
        return list;
    }
}　　

Python:

class Solution:
    # @param {integer[]} nums
    # @return {string[]}
    def summaryRanges(self, nums):
        ranges = []
        if not nums:
            return ranges
 
        start, end = nums[0], nums[0]
        for i in xrange(1, len(nums) + 1):
            if i < len(nums) and nums[i] == end + 1:
                end = nums[i]
            else:
                interval = str(start)
                if start != end:
                    interval += "->" + str(end)
                ranges.append(interval)
                if i < len(nums):
                    start = end = nums[i]
 
        return ranges　　

Python:

class Solution(object):
    def summaryRanges(self, nums):
        """
        :type nums: List[int]
        :rtype: List[str]
        """
 
        ranges = []
        for n in nums:
            if not ranges or n > ranges[-1][-1] + 1:
                ranges += [],
            ranges[-1][1:] = n,
 
        return ['->'.join(map(str, r)) for r in ranges]　　

Python:

class Solution(object):
    def summaryRanges(self, nums):
        """
        :type nums: List[int]
        :rtype: List[str]
        """
        ranges, r = [], []
        for n in nums:
            if n-1 not in r:
                r = []
                ranges += r,
            r[1:] = n,
            print r, ranges
        return ['->'.join(map(str, r)) for r in ranges]

C++:

class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        vector<string> res;
        int i = 0, n = nums.size();
        while (i < n) {
            int j = 1;
            while (i + j < n && nums[i + j] - nums[i] == j) ++j;
            res.push_back(j <= 1 ? to_string(nums[i]) : to_string(nums[i]) + "->" + to_string(nums[i + j - 1]));
            i += j;
        }
        return res;
    }
};

C++:

class Solution {
public:
    vector<string> summaryRanges(vector<int>& nums) {
        const int size_n = nums.size();
        vector<string> res;
        if ( 0 == size_n) return res;
        for (int i = 0; i < size_n;) {
            int start = i, end = i;
            while (end + 1 < size_n && nums[end+1] == nums[end] + 1) end++;
            if (end > start) res.push_back(to_string(nums[start]) + "->" + to_string(nums[end]));
            else res.push_back(to_string(nums[start]));
            i = end+1;
        }
        return res;
    }
};

　　

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