LeetCode 330. Patching Array

      要注意有超int的情况

typedef long long int _int;
class Solution {
public:
    int minPatches(vector<int>& nums, int n) {
        
        _int start = 1;
        _int pre=0;
        
        int ans=0;
        
        for(int i=0;i<nums.size();i++)
        {
            
            while(start<nums[i])
            {
                ans++;
                start = start + pre;
                pre=start;
                if(pre>=n)
                    return ans;
                start++;
            }
            
            start = (_int)nums[i] + pre;
            pre = start;
            start++;
            if(pre>=n)
                return ans;
        }
        
        
        while(start<=n)
        {
            ans++;
            start=start+pre;
            pre=start;
            start++;
        }
        
        return ans;
        
    }
};