AcWing 113. 特殊排序（二分）

传送门

// Forward declaration of compare API.
// bool compare(int a, int b);
// return bool means whether a is less than b.

class Solution {
public:
    vector<int> specialSort(int N) {
        vector<int>ans;
        ans.push_back(1);
        for(int i = 2;i <= N; i++){
            int l = 0,r = ans.size() - 1;
            while(l <= r){
                int mid = (l + r) / 2;
                if(compare(ans[mid],i))
                    l = mid + 1;
                else
                    r = mid - 1;
            }
            ans.push_back(i);
            for(int j = ans.size() - 2;j > r; j--)
                swap(ans[j],ans[j + 1]);
            if(compare(i,ans[r]))
                swap(ans[r],ans[r + 1]);
        }
        return ans;
    }
};