n[n[i]] #easy


https://leetcode.com/problems/build-array-from-permutation/description/

https://leetcode.com/problems/find-minimum-time-to-reach-last-room-i/description


Fastest path in graph #medium #bfs

https://leetcode.com/problems/find-minimum-time-to-reach-last-room-ii/description/


Fastest travel in graph, alternating dt=1,2 #medium #bfs

Permutations of even-odd position sums equal #hard #dp #math


https://leetcode.com/problems/count-number-of-balanced-permutations/description/

https://leetcode.com/problems/minimum-equal-sum-of-two-arrays-after-replacing-zeros/description/


Min equal array sum, fill zeros #medium

3 odds #easy #bitmask


https://leetcode.com/problems/three-consecutive-odds/description/

Triple digit even numbers from digits #easy #backtrack


https://leetcode.com/problems/finding-3-digit-even-numbers/description

String length after t shifts c=c+1,z=ab #medium #dp



https://leetcode.com/problems/total-characters-in-string-after-transformations-i/description

t steps to convert char into next nums[c] chars #hard #dp #math


https://leetcode.com/problems/total-characters-in-string-after-transformations-ii/description

https://leetcode.com/problems/longest-unequal-adjacent-groups-subsequence-i/description


Longest subsequence alterating g #easy #gready

https://leetcode.com/problems/longest-unequal-adjacent-groups-subsequence-ii/description


Longest subsequence humming distance 1, alterating groups #medium #dp

https://leetcode.com/problems/sort-colors/description


Sort 0,1,2 array #medium #two_pointers

https://leetcode.com/problems/painting-a-grid-with-three-different-colors/description


Ways to 3-color m*n grid, no adjucents #hard #dp #matrix

https://leetcode.com/problems/type-of-triangle/description/

Triangle type by lengths #easy

https://leetcode.com/problems/zero-array-transformation-i/description/


Can intersecting intervals decrease an array #medium #line_sweep

https://leetcode.com/problems/set-matrix-zeroes/description/

Zero-fy rows and columns #medium

https://leetcode.com/problems/zero-array-transformation-iii/description


Max removed queries still zero-fy an array #medium #heap

https://leetcode.com/problems/find-the-maximum-sum-of-node-values/description/

Max sum by k-xoring edges #hard #tree #dp

Indices with x #easy


https://leetcode.com/problems/find-words-containing-character/description/

https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/description/


2131. Longest Palindrome by Concatenating Two Letter Words