# Math

- [Geometry](/oj/math/geometry-1.md)
- [Largest Triangle Area](/oj/math/geometry-1/largest-triangle-area.md): https://leetcode.com/problems/largest-triangle-area/
- [593. Valid Square](/oj/math/geometry-1/593.-valid-square.md): https://leetcode.com/problems/valid-square/
- [Count Primes](/oj/math/count-primes.md): https://leetcode.com/problems/count-primes/description/
- [441. Arranging Coins](/oj/math/arranging-coins.md): https://leetcode.com/problems/arranging-coins/description/
- [Permutation Sequence](/oj/math/permutation-sequence.md)
- [Range Addition II](/oj/math/range-addition-ii.md)
- [进制转换](/oj/math/jin-zhi-zhuan-huan.md)
- [Excel Sheet Column Title](/oj/math/jin-zhi-zhuan-huan/excel-sheet-column-title.md)
- [Excel Sheet Column Number](/oj/math/jin-zhi-zhuan-huan/excel-sheet-column-number.md)
- [405. Convert a Number to Hexadecimal](/oj/math/jin-zhi-zhuan-huan/405.-convert-a-number-to-hexadecimal.md): https://leetcode.com/problems/convert-a-number-to-hexadecimal/
- [660 Remove 9](/oj/math/jin-zhi-zhuan-huan/660-remove-9.md)
- [Maximum Product of Three Numbers](/oj/math/maximum-product-of-three-numbers.md)
- [Power of Three](/oj/math/power-of-three.md)
- [Ugly Number](/oj/math/ugly-number.md)
- [1344. Angle Between Hands of a Clock](/oj/math/1344.-angle-between-hands-of-a-clock.md): https://leetcode.com/problems/angle-between-hands-of-a-clock/
- [66. Plus One](/oj/math/plus-one.md): https://leetcode.com/problems/plus-one/description/
- [780. Reaching Points](/oj/math/780.-reaching-points.md): https://leetcode.com/problems/reaching-points/
- [564. Find the Closest Palindrome](/oj/math/564.-find-the-closest-palindrome.md): https://leetcode.com/problems/find-the-closest-palindrome/description/
- [Sqrt(x)](/oj/math/sqrtx.md)
- [Valid Perfect Square](/oj/math/sqrtx/valid-perfect-square.md)
- [1390. Four Divisors](/oj/math/sqrtx/1390.-four-divisors.md): https://leetcode.com/problems/four-divisors/
- [Factorial Trailing Zeroes](/oj/math/factorial-trailing-zeroes.md)
- [Strobogrammatic Number](/oj/math/strobogrammatic-number.md): https://leetcode.com/problems/strobogrammatic-number/description/
- [296. Best Meeting Point](/oj/math/296.-best-meeting-point.md)
- [排列组合](/oj/math/pai-lie-zu-he.md)
- [1643. Kth Smallest Instructions](/oj/math/pai-lie-zu-he/1643.-kth-smallest-instructions.md): https://leetcode.com/problems/kth-smallest-instructions/
- [Perfect Number](/oj/math/perfect-number.md)
- [加法](/oj/math/jia-fa.md)
- [67. Add Binary](/oj/math/jia-fa/add-binary.md): https://leetcode.com/problems/add-binary/description/
- [Add Strings](/oj/math/jia-fa/add-strings.md)
- [Multiply Strings](/oj/math/jia-fa/multiply-strings.md): https://leetcode.com/problems/multiply-strings/description/
- [Nth Digit](/oj/math/nth-digit.md)
- [Roman to Integer](/oj/math/roman-to-integer.md)
- [Integer to Roman](/oj/math/roman-to-integer/integer-to-roman.md)
- [Integer to English Words](/oj/math/roman-to-integer/integer-to-english-words.md): https://leetcode.com/problems/integer-to-english-words/description/
- [Pow(x, n)](/oj/math/powx-n.md): https://leetcode.com/problems/powx-n/description/
- [Divide Two Integers](/oj/math/divide-two-integers.md): https://leetcode.com/problems/divide-two-integers/description/
- [GCD](/oj/math/gcd.md)
- [Geometry](/oj/math/geometry.md)
- [Max Points on a Line](/oj/math/geometry/max-points-on-a-line.md): https://leetcode.com/problems/max-points-on-a-line/description/
- [Rectangle Area](/oj/math/geometry/rectangle-area.md)
- [Line Reflection](/oj/math/geometry/line-reflection.md)
- [Super Pow](/oj/math/super-pow.md)
- [829. Consecutive Numbers Sum](/oj/math/829.-consecutive-numbers-sum.md): https://leetcode.com/problems/consecutive-numbers-sum/
- [找规律](/oj/math/zhao-gui-lv.md)
- [Rotate Function](/oj/math/zhao-gui-lv/rotate-function.md)
- [Bulb Switcher](/oj/math/zhao-gui-lv/bulb-switcher.md): https://leetcode.com/problems/bulb-switcher/description/
- [Add Digits](/oj/math/zhao-gui-lv/add-digits.md)
- [1247. Minimum Swaps to Make Strings Equal](/oj/math/zhao-gui-lv/1247.-minimum-swaps-to-make-strings-equal.md): https://leetcode.com/contest/weekly-contest-161/problems/minimum-swaps-to-make-strings-equal/
- [Bulb Switcher II](/oj/math/zhao-gui-lv/bulb-switcher-ii.md)
- [1503. Last Moment Before All Ants Fall Out of a Plank](/oj/math/zhao-gui-lv/1503.-last-moment-before-all-ants-fall-out-of-a-plank.md)
- [Next Closest Time](/oj/math/next-closest-time.md)
- [1362. Closest Divisors](/oj/math/1362.-closest-divisors.md): https://leetcode.com/problems/closest-divisors/
- [Missing Ranges](/oj/math/missing-ranges.md)
- [Strobogrammatic Number III](/oj/math/strobogrammatic-number-iii.md)
- [1154. Day of the Year](/oj/math/1154.-day-of-the-year.md): https://leetcode.com/problems/day-of-the-year/
- [1360. Number of Days Between Two Dates](/oj/math/1360.-number-of-days-between-two-dates.md): https://leetcode.com/problems/number-of-days-between-two-dates/
- [Majority Element](/oj/math/majority-element.md)
- [Majority Element II](/oj/math/majority-element/majority-element-ii.md)
- [311. Sparse Matrix Multiplication](/oj/math/sparse-matrix-multiplication.md): https://leetcode.com/problems/sparse-matrix-multiplication/description/
- [Maximum Swap](/oj/math/maximum-swap.md)
- [Reservoir Sampling](/oj/math/reservoir-sampling.md)
- [Random Pick Index](/oj/math/reservoir-sampling/random-pick-index.md): https://leetcode.com/problems/random-pick-index/description/
- [382. Linked List Random Node](/oj/math/reservoir-sampling/linked-list-random-node.md): https://leetcode.com/problems/linked-list-random-node/description/
- [Integer Break](/oj/math/integer-break.md)
- [Largest Perimeter Triangle](/oj/math/largest-perimeter-triangle.md)
- [1363. Largest Multiple of Three](/oj/math/1363.-largest-multiple-of-three.md): https://leetcode.com/problems/largest-multiple-of-three/
- [Binary Prefix Divisible By 5](/oj/math/binary-prefix-divisible-by-5.md)
- [随机数](/oj/math/sui-ji-shu.md)
- [470. Implement Rand10() Using Rand7()](/oj/math/sui-ji-shu/470.-implement-rand10-using-rand7.md): https://leetcode.com/problems/implement-rand10-using-rand7/description/
- [478. Generate Random Point in a Circle](/oj/math/sui-ji-shu/478.-generate-random-point-in-a-circle.md): https://leetcode.com/problems/generate-random-point-in-a-circle/description/
- [528. Random Pick with Weight](/oj/math/sui-ji-shu/528.-random-pick-with-weight.md): https://leetcode.com/problems/random-pick-with-weight/description/
- [710. Random Pick with Blacklist](/oj/math/sui-ji-shu/710.-random-pick-with-blacklist.md): https://leetcode.com/problems/random-pick-with-blacklist/description/
- [381. Insert/Del GetRandom O(1)-Duplicates allowed](/oj/math/sui-ji-shu/381.-insert-del-getrandom-o-1-duplicates-allowed.md)
