Given a sorted integer array without duplicates, return the summary of its ranges.
Example 1:
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| 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.
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Example 2:
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| 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.
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双指针
指针begin记录continuous range第一个数, end记录continuous range的最后一个数. 若发现某个i和前面的不连续, 将begin和end统计成字符串存储到vector中, 并更新begin和end为nums[i]
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| class Solution {
public:
vector<string> summaryRanges(vector<int>& nums) {
vector<string> vc;
if(nums.empty())
return vc;
int begin = nums.front();
int end = nums.front();
for(int i = 1; ; ++i)
{
if(i < nums.size() && nums[i] == nums[i-1] + 1)
{
++end;
}
else
{
if(begin == end)
{
vc.push_back(to_string(begin));
}
else
{
vc.push_back(to_string(begin) + "->" + to_string(end));
}
if(i == nums.size())
break;
end = begin = nums[i];
}
}
return vc;
}
};
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