53-II.0～n-1中缺失的数字 #

class Solution {
    public int missingNumber(int[] nums) {
        int l = 0,r = nums.length -1;
        while(l<=r){
            int m = (l+r)/2;
            if(nums[m] == m)l = m+1;
            else r = m - 1;
        }
        return l;
    }
}