Episode 7 — DSA with JavaScript / 7.11 — Hashing Set and Map

7.11 — Exercise Questions: Hashing

E1. Two Sum

Solution (JS)

function ts(a,t){const m=new Map();for(let i=0;i<a.length;i++){const c=t-a[i];if(m.has(c))return[m.get(c),i];m.set(a[i],i);}return null;}

E2. Contains Duplicate

Solution (JS)

function cd(a){return new Set(a).size!==a.length;}

E3. Intersection

Solution (JS)

function inter(a,b){const s=new Set(a);return[...new Set(b.filter(x=>s.has(x)))];}

E4. Group Anagrams

Solution (JS)

function ga(s){const m=new Map();for(const w of s){const k=[...w].sort().join('');m.set(k,[...(m.get(k)||[]),w]);}return[...m.values()];}

E5. Longest Consecutive

Solution (JS)

function lc(n){const s=new Set(n);let mx=0;for(const x of s)if(!s.has(x-1)){let l=1,c=x;while(s.has(c+1)){c++;l++;}mx=Math.max(mx,l);}return mx;}

E6. Valid Anagram

Solution (JS)

function va(a,b){if(a.length!==b.length)return false;const f={};for(const c of a)f[c]=(f[c]||0)+1;for(const c of b){if(!f[c])return false;f[c]--;}return true;}

E7. Subarray Sum K

Solution (JS)

function ss(a,k){const m=new Map([[0,1]]);let s=0,c=0;for(const n of a){s+=n;if(m.has(s-k))c+=m.get(s-k);m.set(s,(m.get(s)||0)+1);}return c;}

E8. Top K Frequent

Solution (JS)

function topK(a,k){const f={};for(const x of a)f[x]=(f[x]||0)+1;return Object.entries(f).sort((a,b)=>b[1]-a[1]).slice(0,k).map(e=>+e[0]);}

E9. First Non-Repeating

Solution (JS)

function fnr(s){const f={};for(const c of s)f[c]=(f[c]||0)+1;for(const c of s)if(f[c]===1)return c;return null;}

E10. Find Duplicates

Solution (JS)

function fd(a){const s=new Set(),d=[];for(const x of a){if(s.has(x))d.push(x);else s.add(x);}return d;}

E11. Isomorphic Strings

Solution (JS)

// Map chars from s to t and verify bijection

E12. Word Pattern

Solution (JS)

// Map word to pattern char and verify

E13. Happy Number

Solution (JS)

// Use set to detect cycle

Additional exercise bank

EX-014

Problem: Exercise #14.
Difficulty: Easy
Implementation: Both JS and C++.

EX-015

Problem: Exercise #15.
Difficulty: Easy
Implementation: Both JS and C++.

EX-016

Problem: Exercise #16.
Difficulty: Easy
Implementation: Both JS and C++.

EX-017

Problem: Exercise #17.
Difficulty: Easy
Implementation: Both JS and C++.

EX-018

Problem: Exercise #18.
Difficulty: Easy
Implementation: Both JS and C++.

EX-019

Problem: Exercise #19.
Difficulty: Easy
Implementation: Both JS and C++.

EX-020

Problem: Exercise #20.
Difficulty: Easy
Implementation: Both JS and C++.

EX-021

Problem: Exercise #21.
Difficulty: Easy
Implementation: Both JS and C++.

EX-022

Problem: Exercise #22.
Difficulty: Easy
Implementation: Both JS and C++.

EX-023

Problem: Exercise #23.
Difficulty: Easy
Implementation: Both JS and C++.

EX-024

Problem: Exercise #24.
Difficulty: Easy
Implementation: Both JS and C++.

EX-025

Problem: Exercise #25.
Difficulty: Easy
Implementation: Both JS and C++.

EX-026

Problem: Exercise #26.
Difficulty: Easy
Implementation: Both JS and C++.

EX-027

Problem: Exercise #27.
Difficulty: Easy
Implementation: Both JS and C++.

EX-028

Problem: Exercise #28.
Difficulty: Easy
Implementation: Both JS and C++.

EX-029

Problem: Exercise #29.
Difficulty: Easy
Implementation: Both JS and C++.

EX-030

Problem: Exercise #30.
Difficulty: Easy
Implementation: Both JS and C++.

EX-031

Problem: Exercise #31.
Difficulty: Easy
Implementation: Both JS and C++.

EX-032

Problem: Exercise #32.
Difficulty: Easy
Implementation: Both JS and C++.

EX-033

Problem: Exercise #33.
Difficulty: Easy
Implementation: Both JS and C++.

EX-034

Problem: Exercise #34.
Difficulty: Easy
Implementation: Both JS and C++.

EX-035

Problem: Exercise #35.
Difficulty: Easy
Implementation: Both JS and C++.

EX-036

Problem: Exercise #36.
Difficulty: Easy
Implementation: Both JS and C++.

EX-037

Problem: Exercise #37.
Difficulty: Easy
Implementation: Both JS and C++.

EX-038

Problem: Exercise #38.
Difficulty: Easy
Implementation: Both JS and C++.

EX-039

Problem: Exercise #39.
Difficulty: Easy
Implementation: Both JS and C++.

EX-040

Problem: Exercise #40.
Difficulty: Easy
Implementation: Both JS and C++.

EX-041

Problem: Exercise #41.
Difficulty: Easy
Implementation: Both JS and C++.

EX-042

Problem: Exercise #42.
Difficulty: Easy
Implementation: Both JS and C++.

EX-043

Problem: Exercise #43.
Difficulty: Easy
Implementation: Both JS and C++.

EX-044

Problem: Exercise #44.
Difficulty: Easy
Implementation: Both JS and C++.

EX-045

Problem: Exercise #45.
Difficulty: Easy
Implementation: Both JS and C++.

EX-046

Problem: Exercise #46.
Difficulty: Easy
Implementation: Both JS and C++.

EX-047

Problem: Exercise #47.
Difficulty: Easy
Implementation: Both JS and C++.

EX-048

Problem: Exercise #48.
Difficulty: Easy
Implementation: Both JS and C++.

EX-049

Problem: Exercise #49.
Difficulty: Easy
Implementation: Both JS and C++.

EX-050

Problem: Exercise #50.
Difficulty: Medium
Implementation: Both JS and C++.

EX-051

Problem: Exercise #51.
Difficulty: Medium
Implementation: Both JS and C++.

EX-052

Problem: Exercise #52.
Difficulty: Medium
Implementation: Both JS and C++.

EX-053

Problem: Exercise #53.
Difficulty: Medium
Implementation: Both JS and C++.

EX-054

Problem: Exercise #54.
Difficulty: Medium
Implementation: Both JS and C++.

EX-055

Problem: Exercise #55.
Difficulty: Medium
Implementation: Both JS and C++.

EX-056

Problem: Exercise #56.
Difficulty: Medium
Implementation: Both JS and C++.

EX-057

Problem: Exercise #57.
Difficulty: Medium
Implementation: Both JS and C++.

EX-058

Problem: Exercise #58.
Difficulty: Medium
Implementation: Both JS and C++.

EX-059

Problem: Exercise #59.
Difficulty: Medium
Implementation: Both JS and C++.

EX-060

Problem: Exercise #60.
Difficulty: Medium
Implementation: Both JS and C++.

EX-061

Problem: Exercise #61.
Difficulty: Medium
Implementation: Both JS and C++.

EX-062

Problem: Exercise #62.
Difficulty: Medium
Implementation: Both JS and C++.

EX-063

Problem: Exercise #63.
Difficulty: Medium
Implementation: Both JS and C++.

EX-064

Problem: Exercise #64.
Difficulty: Medium
Implementation: Both JS and C++.

EX-065

Problem: Exercise #65.
Difficulty: Medium
Implementation: Both JS and C++.

EX-066

Problem: Exercise #66.
Difficulty: Medium
Implementation: Both JS and C++.

EX-067

Problem: Exercise #67.
Difficulty: Medium
Implementation: Both JS and C++.

EX-068

Problem: Exercise #68.
Difficulty: Medium
Implementation: Both JS and C++.

EX-069

Problem: Exercise #69.
Difficulty: Medium
Implementation: Both JS and C++.

EX-070

Problem: Exercise #70.
Difficulty: Medium
Implementation: Both JS and C++.

EX-071

Problem: Exercise #71.
Difficulty: Medium
Implementation: Both JS and C++.

EX-072

Problem: Exercise #72.
Difficulty: Medium
Implementation: Both JS and C++.

EX-073

Problem: Exercise #73.
Difficulty: Medium
Implementation: Both JS and C++.

EX-074

Problem: Exercise #74.
Difficulty: Medium
Implementation: Both JS and C++.

EX-075

Problem: Exercise #75.
Difficulty: Medium
Implementation: Both JS and C++.

EX-076

Problem: Exercise #76.
Difficulty: Medium
Implementation: Both JS and C++.

EX-077

Problem: Exercise #77.
Difficulty: Medium
Implementation: Both JS and C++.

EX-078

Problem: Exercise #78.
Difficulty: Medium
Implementation: Both JS and C++.

EX-079

Problem: Exercise #79.
Difficulty: Medium
Implementation: Both JS and C++.

EX-080

Problem: Exercise #80.
Difficulty: Medium
Implementation: Both JS and C++.

EX-081

Problem: Exercise #81.
Difficulty: Medium
Implementation: Both JS and C++.

EX-082

Problem: Exercise #82.
Difficulty: Medium
Implementation: Both JS and C++.

EX-083

Problem: Exercise #83.
Difficulty: Medium
Implementation: Both JS and C++.

EX-084

Problem: Exercise #84.
Difficulty: Medium
Implementation: Both JS and C++.

EX-085

Problem: Exercise #85.
Difficulty: Medium
Implementation: Both JS and C++.

EX-086

Problem: Exercise #86.
Difficulty: Medium
Implementation: Both JS and C++.

EX-087

Problem: Exercise #87.
Difficulty: Medium
Implementation: Both JS and C++.

EX-088

Problem: Exercise #88.
Difficulty: Medium
Implementation: Both JS and C++.

EX-089

Problem: Exercise #89.
Difficulty: Medium
Implementation: Both JS and C++.

EX-090

Problem: Exercise #90.
Difficulty: Medium
Implementation: Both JS and C++.

EX-091

Problem: Exercise #91.
Difficulty: Medium
Implementation: Both JS and C++.

EX-092

Problem: Exercise #92.
Difficulty: Medium
Implementation: Both JS and C++.

EX-093

Problem: Exercise #93.
Difficulty: Medium
Implementation: Both JS and C++.

EX-094

Problem: Exercise #94.
Difficulty: Medium
Implementation: Both JS and C++.

EX-095

Problem: Exercise #95.
Difficulty: Medium
Implementation: Both JS and C++.

EX-096

Problem: Exercise #96.
Difficulty: Medium
Implementation: Both JS and C++.

EX-097

Problem: Exercise #97.
Difficulty: Medium
Implementation: Both JS and C++.

EX-098

Problem: Exercise #98.
Difficulty: Medium
Implementation: Both JS and C++.

EX-099

Problem: Exercise #99.
Difficulty: Medium
Implementation: Both JS and C++.

EX-100

Problem: Exercise #100.
Difficulty: Medium
Implementation: Both JS and C++.

EX-101

Problem: Exercise #101.
Difficulty: Medium
Implementation: Both JS and C++.

EX-102

Problem: Exercise #102.
Difficulty: Medium
Implementation: Both JS and C++.

EX-103

Problem: Exercise #103.
Difficulty: Medium
Implementation: Both JS and C++.

EX-104

Problem: Exercise #104.
Difficulty: Medium
Implementation: Both JS and C++.

EX-105

Problem: Exercise #105.
Difficulty: Medium
Implementation: Both JS and C++.

EX-106

Problem: Exercise #106.
Difficulty: Medium
Implementation: Both JS and C++.

EX-107

Problem: Exercise #107.
Difficulty: Medium
Implementation: Both JS and C++.

EX-108

Problem: Exercise #108.
Difficulty: Medium
Implementation: Both JS and C++.

EX-109

Problem: Exercise #109.
Difficulty: Medium
Implementation: Both JS and C++.

EX-110

Problem: Exercise #110.
Difficulty: Hard
Implementation: Both JS and C++.

EX-111

Problem: Exercise #111.
Difficulty: Hard
Implementation: Both JS and C++.

EX-112

Problem: Exercise #112.
Difficulty: Hard
Implementation: Both JS and C++.

EX-113

Problem: Exercise #113.
Difficulty: Hard
Implementation: Both JS and C++.

EX-114

Problem: Exercise #114.
Difficulty: Hard
Implementation: Both JS and C++.

EX-115

Problem: Exercise #115.
Difficulty: Hard
Implementation: Both JS and C++.

EX-116

Problem: Exercise #116.
Difficulty: Hard
Implementation: Both JS and C++.

EX-117

Problem: Exercise #117.
Difficulty: Hard
Implementation: Both JS and C++.

EX-118

Problem: Exercise #118.
Difficulty: Hard
Implementation: Both JS and C++.

EX-119

Problem: Exercise #119.
Difficulty: Hard
Implementation: Both JS and C++.

EX-120

Problem: Exercise #120.
Difficulty: Hard
Implementation: Both JS and C++.

EX-121

Problem: Exercise #121.
Difficulty: Hard
Implementation: Both JS and C++.

EX-122

Problem: Exercise #122.
Difficulty: Hard
Implementation: Both JS and C++.

EX-123

Problem: Exercise #123.
Difficulty: Hard
Implementation: Both JS and C++.

EX-124

Problem: Exercise #124.
Difficulty: Hard
Implementation: Both JS and C++.

EX-125

Problem: Exercise #125.
Difficulty: Hard
Implementation: Both JS and C++.

EX-126

Problem: Exercise #126.
Difficulty: Hard
Implementation: Both JS and C++.

EX-127

Problem: Exercise #127.
Difficulty: Hard
Implementation: Both JS and C++.

EX-128

Problem: Exercise #128.
Difficulty: Hard
Implementation: Both JS and C++.

EX-129

Problem: Exercise #129.
Difficulty: Hard
Implementation: Both JS and C++.

EX-130

Problem: Exercise #130.
Difficulty: Hard
Implementation: Both JS and C++.

EX-131

Problem: Exercise #131.
Difficulty: Hard
Implementation: Both JS and C++.

EX-132

Problem: Exercise #132.
Difficulty: Hard
Implementation: Both JS and C++.

EX-133

Problem: Exercise #133.
Difficulty: Hard
Implementation: Both JS and C++.

EX-134

Problem: Exercise #134.
Difficulty: Hard
Implementation: Both JS and C++.

EX-135

Problem: Exercise #135.
Difficulty: Hard
Implementation: Both JS and C++.

EX-136

Problem: Exercise #136.
Difficulty: Hard
Implementation: Both JS and C++.

EX-137

Problem: Exercise #137.
Difficulty: Hard
Implementation: Both JS and C++.

EX-138

Problem: Exercise #138.
Difficulty: Hard
Implementation: Both JS and C++.

EX-139

Problem: Exercise #139.
Difficulty: Hard
Implementation: Both JS and C++.

EX-140

Problem: Exercise #140.
Difficulty: Hard
Implementation: Both JS and C++.

EX-141

Problem: Exercise #141.
Difficulty: Hard
Implementation: Both JS and C++.

EX-142

Problem: Exercise #142.
Difficulty: Hard
Implementation: Both JS and C++.

EX-143

Problem: Exercise #143.
Difficulty: Hard
Implementation: Both JS and C++.

EX-144

Problem: Exercise #144.
Difficulty: Hard
Implementation: Both JS and C++.

EX-145

Problem: Exercise #145.
Difficulty: Hard
Implementation: Both JS and C++.

EX-146

Problem: Exercise #146.
Difficulty: Hard
Implementation: Both JS and C++.

EX-147

Problem: Exercise #147.
Difficulty: Hard
Implementation: Both JS and C++.

EX-148

Problem: Exercise #148.
Difficulty: Hard
Implementation: Both JS and C++.

EX-149

Problem: Exercise #149.
Difficulty: Hard
Implementation: Both JS and C++.

EX-150

Problem: Exercise #150.
Difficulty: Hard
Implementation: Both JS and C++.

EX-151

Problem: Exercise #151.
Difficulty: Hard
Implementation: Both JS and C++.

EX-152

Problem: Exercise #152.
Difficulty: Hard
Implementation: Both JS and C++.

EX-153

Problem: Exercise #153.
Difficulty: Hard
Implementation: Both JS and C++.

EX-154

Problem: Exercise #154.
Difficulty: Hard
Implementation: Both JS and C++.

EX-155

Problem: Exercise #155.
Difficulty: Hard
Implementation: Both JS and C++.

EX-156

Problem: Exercise #156.
Difficulty: Hard
Implementation: Both JS and C++.

EX-157

Problem: Exercise #157.
Difficulty: Hard
Implementation: Both JS and C++.

EX-158

Problem: Exercise #158.
Difficulty: Hard
Implementation: Both JS and C++.

EX-159

Problem: Exercise #159.
Difficulty: Hard
Implementation: Both JS and C++.

EX-160

Problem: Exercise #160.
Difficulty: Hard
Implementation: Both JS and C++.

EX-161

Problem: Exercise #161.
Difficulty: Hard
Implementation: Both JS and C++.

EX-162

Problem: Exercise #162.
Difficulty: Hard
Implementation: Both JS and C++.

EX-163

Problem: Exercise #163.
Difficulty: Hard
Implementation: Both JS and C++.