LeetQuant
Get started free
Study plans

Quant Trader

· 21-day option

Speed, intuition, expected value and market sense — the mental-math and game-theory muscle for trading desks (Optiver, IMC, SIG, Jane Street).

Sign in to track your progress — each problem checks off as you solve it.

01Mental Math & Expected Value

25
Flips Until First Head
ProbabilityOptiverIMC Trading
69%Easy23
Roll Until All Six Faces
ProbabilityGoogleTwo Sigma
41%Medium27
Two Dice Sum to 7
ProbabilityOptiverIMC Trading
85%Easy33
Expected Max of Two Dice
ProbabilityOptiverIMC Trading
41%Medium6
Sum 1 to 100
Brain TeasersJane StreetGoldman Sachs
72%Easy2
Trailing Zeros in 100!
Brain TeasersGoldman SachsJ.P. Morgan
52%Easy9
Last Digit of 2^100
Brain TeasersGoldman SachsMorgan Stanley
60%Easy5
Clock Hands at 3:15
Brain TeasersMorgan StanleyBarclays
58%Easy

02Market Making & Games

137
Make a Market on Two Dice
Market Making & GamesOptiverSIG / Susquehanna
87%Easy138
Fair Value of a Loaded Die
Market Making & GamesOptiverIMC Trading
68%Medium139
Roll, Keep or Re-roll
Market Making & GamesJane StreetSIG / Susquehanna
45%Medium143
Odds to Probability
Market Making & GamesFlow TradersOptiver
39%Easy144
Quoting Against Informed Flow
Market Making & GamesCitadel SecuritiesSIG / Susquehanna
46%Hard151
Skewing Off an Inventory
Market Making & GamesOptiverFlow Traders
76%Easy145
Kelly with 2-to-1 Odds
Market Making & GamesSIG / SusquehannaDRW
40%Medium140
The Red–Black Card Game
Market Making & GamesJane StreetCitadel Securities
39%Hard153
The House Edge in European Roulette
Market Making & GamesSIG / SusquehannaFive Rings
52%Easy

03Probability & Game Theory

21
Coin Toss — Two Heads
ProbabilityJane Street
53%Easy22
Monty Hall
ProbabilityGoldman SachsMorgan Stanley
56%Easy32
Two Children
ProbabilityGoldman SachsMorgan Stanley
66%Easy28
Bayes — Disease Test
ProbabilityGoldman SachsTwo Sigma
55%Medium24
Birthday Problem
ProbabilityGoldman SachsCitadel
52%Medium26
Drunk Passenger
ProbabilityJane StreetCitadel
55%Medium34
Russian Roulette — Spin?
ProbabilityJane StreetCitadel
62%Medium29
Broken Stick Triangle
ProbabilityJane StreetCitadel
43%Medium1
Screwy Pirates
Brain TeasersJane StreetOptiver
51%Hard146
Two-Thirds of the Average
Market Making & GamesJane StreetOptiver
65%Medium

04Brain Teasers & Logic

3
Two Eggs, 100 Floors
Brain TeasersGoogleGoldman Sachs
31%Medium4
Horse Race — Top 3
Brain TeasersGoogleTwo Sigma
42%Medium7
100 Lockers
Brain TeasersGoogleTwo Sigma
62%Medium8
Poisoned Wine
Brain TeasersGoogleJane Street
35%Medium10
Mislabeled Jars
Brain TeasersJane StreetOptiver
59%Medium

05Options Intuition & Greeks

121
Delta of an ATM Call
Options & GreeksOptiverIMC Trading
61%Easy123
Gamma Near Expiry
Options & GreeksOptiverIMC Trading
66%Medium122
Delta of a Forward
Options & GreeksOptiverIMC Trading
73%Easy124
Most Negative Put Delta
Options & GreeksGoldman SachsOptiver
66%Easy125
Sign of Theta
Options & GreeksOptiverSIG / Susquehanna
71%Medium

06Fair Value & Pricing

104
Put-Call Parity
FinanceGoldman SachsMorgan Stanley
66%Easy108
Futures Fair Value
FinanceGoldman SachsOptiver
63%Easy106
Risk-Neutral Probability
FinanceGoldman SachsJ.P. Morgan
81%Medium

07Coding & Algorithms

78
Two SumLeetCode
Algorithms & NumericalGoogleDE Shaw
Easy86
Best Time to Buy and Sell StockLeetCode
Algorithms & NumericalTwo SigmaDE Shaw
Medium94
Best Time to Buy and Sell Stock IILeetCode
Algorithms & NumericalOptiverJane Street
Medium83
Maximum Subarray (Kadane)LeetCode
Algorithms & NumericalTwo SigmaDE Shaw
Medium95
Gas StationLeetCode
Algorithms & NumericalJane StreetCitadel
Medium96
Jump GameLeetCode
Algorithms & NumericalGoogleDE Shaw
Medium97
Nim GameLeetCode
Algorithms & NumericalJane StreetSIG / Susquehanna
Easy98
Predict the WinnerLeetCode
Algorithms & NumericalJane StreetOptiver
Medium
Follow as a 21-day schedule

Interleaved, easy → hard, mixed daily

1
Day 1

Brain teasers · Mkt making · Probability

21
Coin Toss — Two Heads
ProbabilityJane Street
53%Easy2
Trailing Zeros in 100!
Brain TeasersGoldman SachsJ.P. Morgan
52%Easy137
Make a Market on Two Dice
Market Making & GamesOptiverSIG / Susquehanna
87%Easy
2
Day 2

Coding · Options · Probability

78
Two SumLeetCode
Algorithms & NumericalGoogleDE Shaw
Easy121
Delta of an ATM Call
Options & GreeksOptiverIMC Trading
61%Easy22
Monty Hall
ProbabilityGoldman SachsMorgan Stanley
56%Easy
3
Day 3

Brain teasers · Finance · Mkt making

5
Clock Hands at 3:15
Brain TeasersMorgan StanleyBarclays
58%Easy143
Odds to Probability
Market Making & GamesFlow TradersOptiver
39%Easy104
Put-Call Parity
FinanceGoldman SachsMorgan Stanley
66%Easy
4
Day 4

Coding · Brain teasers · Probability

97
Nim GameLeetCode
Algorithms & NumericalJane StreetSIG / Susquehanna
Easy25
Flips Until First Head
ProbabilityOptiverIMC Trading
69%Easy6
Sum 1 to 100
Brain TeasersJane StreetGoldman Sachs
72%Easy
5
Day 5

Mkt making · Options · Probability

151
Skewing Off an Inventory
Market Making & GamesOptiverFlow Traders
76%Easy27
Two Dice Sum to 7
ProbabilityOptiverIMC Trading
85%Easy122
Delta of a Forward
Options & GreeksOptiverIMC Trading
73%Easy
6
Day 6

Coding · Brain teasers · Mkt making

83
Maximum Subarray (Kadane)LeetCode
Algorithms & NumericalTwo SigmaDE Shaw
Medium9
Last Digit of 2^100
Brain TeasersGoldman SachsMorgan Stanley
60%Easy153
The House Edge in European Roulette
Market Making & GamesSIG / SusquehannaFive Rings
52%Easy
7
Day 7

Coding · Probability

32
Two Children
ProbabilityGoldman SachsMorgan Stanley
66%Easy86
Best Time to Buy and Sell StockLeetCode
Algorithms & NumericalTwo SigmaDE Shaw
Medium
8
Day 8

Brain teasers · Mkt making

3
Two Eggs, 100 Floors
Brain TeasersGoogleGoldman Sachs
31%Medium138
Fair Value of a Loaded Die
Market Making & GamesOptiverIMC Trading
68%Medium
9
Day 9

Finance · Probability

23
Roll Until All Six Faces
ProbabilityGoogleTwo Sigma
41%Medium108
Futures Fair Value
FinanceGoldman SachsOptiver
63%Easy
10
Day 10

Options · Probability

124
Most Negative Put Delta
Options & GreeksGoldman SachsOptiver
66%Easy24
Birthday Problem
ProbabilityGoldman SachsCitadel
52%Medium
11
Day 11

Brain teasers · Mkt making

4
Horse Race — Top 3
Brain TeasersGoogleTwo Sigma
42%Medium139
Roll, Keep or Re-roll
Market Making & GamesJane StreetSIG / Susquehanna
45%Medium
12
Day 12

Coding · Probability

94
Best Time to Buy and Sell Stock IILeetCode
Algorithms & NumericalOptiverJane Street
Medium26
Drunk Passenger
ProbabilityJane StreetCitadel
55%Medium
13
Day 13

Brain teasers · Mkt making

7
100 Lockers
Brain TeasersGoogleTwo Sigma
62%Medium145
Kelly with 2-to-1 Odds
Market Making & GamesSIG / SusquehannaDRW
40%Medium
14
Day 14

Coding · Options

95
Gas StationLeetCode
Algorithms & NumericalJane StreetCitadel
Medium123
Gamma Near Expiry
Options & GreeksOptiverIMC Trading
66%Medium
15
Day 15

Brain teasers · Probability

28
Bayes — Disease Test
ProbabilityGoldman SachsTwo Sigma
55%Medium8
Poisoned Wine
Brain TeasersGoogleJane Street
35%Medium
16
Day 16

Mkt making · Probability

146
Two-Thirds of the Average
Market Making & GamesJane StreetOptiver
65%Medium29
Broken Stick Triangle
ProbabilityJane StreetCitadel
43%Medium
17
Day 17

Coding · Finance

96
Jump GameLeetCode
Algorithms & NumericalGoogleDE Shaw
Medium106
Risk-Neutral Probability
FinanceGoldman SachsJ.P. Morgan
81%Medium
18
Day 18

Brain teasers · Mkt making

10
Mislabeled Jars
Brain TeasersJane StreetOptiver
59%Medium140
The Red–Black Card Game
Market Making & GamesJane StreetCitadel Securities
39%Hard
19
Day 19

Options · Probability

33
Expected Max of Two Dice
ProbabilityOptiverIMC Trading
41%Medium125
Sign of Theta
Options & GreeksOptiverSIG / Susquehanna
71%Medium
20
Day 20

Coding · Brain teasers

98
Predict the WinnerLeetCode
Algorithms & NumericalJane StreetOptiver
Medium1
Screwy Pirates
Brain TeasersJane StreetOptiver
51%Hard
21
Day 21

Mkt making · Probability

144
Quoting Against Informed Flow
Market Making & GamesCitadel SecuritiesSIG / Susquehanna
46%Hard34
Russian Roulette — Spin?
ProbabilityJane StreetCitadel
62%Medium