228. Summary Ranges

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

For example, given

[0,1,2,4,5,7]

, return

["0->2","4->5","7"].

Credits:

Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

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Solution:

class Solution {
public:
vector<string> summaryRanges(vector<int>& nums) {
vector<string> tmp;
int i = 0;
int pre = 0;
if(nums.empty()) return tmp;
pre = nums[0];
for(;i<nums.size();i++){
if(i+1==nums.size()){
if(pre==nums[i]) {tmp.push_back(to_string(pre));}
else {
tmp.push_back(to_string(pre)+"->"+to_string(nums[i]));
}

return tmp;
}
else{
if(nums[i+1]==nums[i]+1) {}
else {
if(pre==nums[i]) {tmp.push_back(to_string(pre));}
else{
tmp.push_back(to_string(pre)+"->"+to_string(nums[i]));
}
pre = nums[i+1];
}
}
}

}
};

心得：主要考虑corner，程序写的比较繁琐，但逻辑比较清楚

运行速度：快