# My binary search solution

• Use binary search to find proper interval, and connect neighbor intervals if necessary.

``````
/**
* Definition for an interval.
* struct Interval {
*     int start;
*     int end;
*     Interval() : start(0), end(0) {}
*     Interval(int s, int e) : start(s), end(e) {}
* };
*/
class SummaryRanges {
vector<Interval> vec;
int find(int val) {
int vlen = vec.size();
if (vlen == 0) {
return -1;
}
int begin = 0;
int end = vlen - 1;
int mid;
while (begin <= end) {
mid = begin + (end - begin) / 2;
// Here <= vs. >
if (vec[mid].start > val) {
end = mid - 1;
}
else {
begin = mid + 1;
}
}
// Here it's important to return end
return end;
}

public:
/** Initialize your data structure here. */
SummaryRanges() {

}

int idx = find(val);
if (idx < 0) {
if (vec.size() > 0 && vec[0].start == val+1) {
vec[0].start = val;
}
else {
Interval inter(val, val);
vec.insert(vec.begin(), inter);
}
}
else {
if (vec[idx].end == val-1) {
vec[idx].end = val;
}
else if (vec[idx].end < val-1) {
Interval inter(val, val);
vec.insert(vec.begin()+idx+1, inter);
idx++;
}
// check latter
if (vec.size() > idx+1 && vec[idx+1].start == vec[idx].end + 1) {
vec[idx].end = vec[idx+1].end;
vec.erase(vec.begin()+idx+1);
}
}
}

vector<Interval> getIntervals() {
return vec;
}
};

/**
* Your SummaryRanges object will be instantiated and called as such:
* SummaryRanges obj = new SummaryRanges();