Swapping two elements in a sorted array

Title, in a sequence of already sorted numbers, swapped two elements. For example:

nums[] = {1,2,3,4,5,6,7,8,9,10}

After swapping two elements (for example, exchanging numbers 5 and 9 ):

nums[] = {1,2,3,4,9,6,7,8,5,10}

The question is how do we find these two elements in the array?

Ideas

Assume that the two elements of the interchange are the x and y , and x < y . The other numbers are Ni . Then the problem can be expressed as:

nums[] = {N1 , N2 , N3 , Ni , x , Ni+2 , ... , y , ...,Nm }

Exchange x and y post

nums[] = {N1 , N2 , N3 , Ni , y , Ni+2 , ... , x , ...,Nm }

First Find Y

You can see that it is y Ni+2 larger and must appear first, so we can define a subscript cur . If nums[cur-1] > nums[cur] nums[cur-1] that's the y we're looking for.

and find X.

xis also the condition of nums[cur-1] > nums[cur] nums[cur] x. One thing to note here is that if you do nums[cur-1] > nums[cur] , then the condition of X is satisfied. If that Ni+2 's the x case, it's the right thing to do. If Ni+2 not x , the following must be the condition, x Replace.

Code

intnullnull;for(int1 ; cur < nums.length ; cur++){    ifnull && nums[cur-1] > nums[cur]){        first = nums[cur-1];    }    //注意不能用else，否则x，y相邻的情况会无法匹配    ifnull && nums[cur-1] > nums[cur]){        secon = nums[cur];    }}

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Swapping two elements in a sorted array