codeforces-practice

100 problems, rated 800 to 1200, solved in order before entering any contest. Each problem is picked to teach a specific idea — not random grinding.

Language: JavaScript / TypeScript

---

Structure

codeforces-practice/
├── problems/       ← one folder per problem  (4A-watermelon/solution.js)
├── contests/       ← one folder per contest  (1234-div2-round-xyz/)
└── notes/          ← patterns, mistakes, anything useful

---

Progress

22 / 100

---

Phase 1 — 800 (Problems 1–20)

#	Problem	Rating	Done
1	4A — Watermelon	800	[d]
2	71A — Way Too Long Words	800	[d]
3	158A — Next Round	800	[d]
4	263A — Beautiful Matrix	800	[d]
5	282A — Bit++	800	[d]
6	339A — Helpful Maths	800	[d]
7	231A — Team	800	[d]
8	50A — Domino Piling	800	[d]
9	791A — Bear and Prime 100	800	[d]
10	1030A — In Search of an Easy Problem	800	[d]
11	617A — Elephant	800	[d]
12	236A — Boy or Girl	800	[d]
13	112A — Petya and Strings	800	[d]
14	268A — Games	800	[d]
15	520A — Raising Bacteria	800	[d]
16	546A — Soldier and Bananas	800	[d]
17	734A — Anton and Danik	800	[d]
18	978A — Remove Duplicates	800	[d]
19	486A — Calculating Function	800	[d]
20	1A — Theatre Square	1000	[d]

---

Phase 2 — 900 (Problems 21–45)

#	Problem	Rating	Done
21	116A — Tram	900	[]
22	144A — Arrival of the General	900	[d]
23	352A — Jeff and Digits	900	[]
24	1285A — Mezo Playing Zoma	900	[d]
25	546B — Soldier and Badges	900	[]
26	381A — Sereja and Dima	900	[]
27	580A — Kefa and First Steps	900	[d]
28	1374A — Required Remainder	900	[]
29	1360A — Minimal Square	900	[]
30	1512A — Spy Detected!	900	[]
31	1605A — AM Deviation	900	[]
32	1234A — Equalize Prices Again	900	[]
33	1703A — YES or YES?	800	[]
34	1722A — Spell Check	900	[]
35	1325A — EhAb AnD gCd	900	[]
36	1409A — Yet Another Two Integers Problem	800	[]
37	1551A — Polycarp and Coins	800	[]
38	1364A — XXXXX	900	[]
39	1296A — Array with Odd Sum	800	[]
40	1278A — Shuffle Hashing	900	[]
41	1437A — Marketing Scheme	900	[]
42	1624A — Plus One on the Subset	800	[]
43	1A — Theatre Square	1000	[]
44	1328A — Divisibility Problem	800	[]
45	1352B — Same Parity Summands	1000	[]

---

Phase 3 — 1000 (Problems 46–70)

#	Problem	Rating	Done
46	768A — Code For 1	1000	[]
47	466A — Cheap Travel	1000	[]
48	1200A — Hotelier	1000	[]
49	455A — Boredom	1000	[]
50	580B — Kefa and Company	1000	[]
51	1133B — Preparation for International Olympiad	1000	[]
52	817C — Really Big Numbers	1000	[]
53	1399A — Remove Smallest	1000	[]
54	1475A — Strange Birthday Party	1000	[]
55	1283A — Minutes Before the New Year	1000	[]
56	1221A — 2048 Game	1000	[]
57	1073B — Vasya and Books	1000	[]
58	1342B — Binary Period	1000	[]
59	1462A — Favorite Sequence	1000	[]
60	1368A — C+=	1000	[]
61	1374B — Multiply by 2, Divide by 6	1000	[]
62	1567A — Domino Disaster	800	[]
63	1579A — Casimir's String Solitaire	1000	[]
64	1650A — Deletions of Two Adjacent Letters	1000	[]
65	1679A — Ants	800	[]
66	1703B — ICPC Balloons	1000	[]
67	1A — Theatre Square	1000	[]
68	1766B — Mahmoud and a Triangle	1000	[]
69	1791B — Following Directions	1000	[]
70	1811A — Insert Digit	1000	[]

---

Phase 4 — 1100 (Problems 71–85)

#	Problem	Rating	Done
71	1030B — Vasya and Cornfield	1100	[]
72	1742B — Increasing	1100	[]
73	1559A — Mocha and Math	1100	[]
74	1400A — String Similarity	1100	[]
75	1553A — Digits Sum	1100	[]
76	1187A — Stickers and Toys	1100	[]
77	1367B — Even Array	1100	[]
78	1092B — Teams Forming	1100	[]
79	961A — Tetris	1100	[]
80	1057A — Booking a Room	1000	[]
81	1352C — K-th Not Divisible by n	1100	[]
82	1461A — String Generation	1100	[]
83	1525A — Potion-making	1100	[]
84	1611A — Make Even	1100	[]
85	1676B — Equal Candies	1100	[]

---

Phase 5 — 1200 (Problems 86–100)

#	Problem	Rating	Done
86	279B — Books	1200	[]
87	381B — Sereja and Suffixes	1200	[]
88	1611C — Polycarp Recovers	1200	[]
89	1360C — Deutsch, Deitvulf and Volleyball	1200	[]
90	1538C — Number of Pairs	1200	[]
91	702B — Powers of Two	1200	[]
92	1343B — Balanced Array	1200	[]
93	1520C — Not Adjacent Matrix	1200	[]
94	1551B — Wonderful Coloring - 1	1200	[]
95	48B — Chilly Willy	1200	[]
96	1364B — Most Beautiful Item	1200	[]
97	1620B — Longest Palindrome	1300	[]
98	1538B — Friends and Candies	1300	[]
99	1433C — Dominant Piranha	1300	[]
100	1398C — Good Subarrays	1400	[]