Medium

LeetCode 3795 note: a shortest-window slide where each value counts once; track each value’s last position, and subtract the left value only if it was the last occurrence

LeetCode 2653 note: values are only -50 to 50, so the fixed window keeps a count array, and each window accumulates upward from -50 to find the x-th smallest negative

LeetCode 1888 note: rotations become length-n windows over s + s; the window’s mismatches against 0101… are diff, and against 1010… they are n - diff

LeetCode 3788 note: build the suffix minimum first, then accumulate the prefix sum from the left and try every split

LeetCode 3694 note: the endpoint is the total displacement minus the removed segment’s displacement; a length-k window tracks that segment and each endpoint goes into a set

LeetCode 2134 note: the 1s end up in a circular window as long as their count, and the swaps needed equal the 0s in that window; slide around the circle for the minimum

LeetCode 3679 note: the rule already decides what must be discarded, so simulate it; the length-w window counts only kept arrivals, and discarded ones must not be subtracted when they leave

LeetCode 2461 note: in a fixed window of length k, all values are distinct exactly when the number of distinct values equals k

LeetCode 1423 note: taking k cards from the ends leaves a contiguous middle of n - k cards; find its minimum sum with a fixed-size window

LeetCode 2841 note: a fixed window of length k keeps a sum and a count map; the number of distinct values is the map’s size, so delete keys that drop to zero

LeetCode 3709 note: times are increasing, so store prefix sums and answer queries with two bisects; always parenthesize mid

LeetCode 3708 note: lengths 1 and 2 always work; from the third element, extend while nums[i] == nums[i-1] + nums[i-2], otherwise reset to 2