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Top rated · Stats

zhaohaikun

Open on Codeforces · Unique solved

Rating2884· International Grandmaster

Bar charts count unique accepted problems (merged with the global problem set for rating and tags). Heatmaps use UTC calendar days. Rating squares are sums of newRating − oldRating from user.rating when System update time falls on that day. Submissions count every row from user.status (all verdicts), paginated until Codeforces has no more rows—heavy accounts can take a few seconds.

Rated contests
76
Unique solved
1,556
Submissions (all)
4,636
Years with activity
2019–2026

Solved by problem rating

Unique accepted problems, bucketed by catalog rating (100‑point bands). Unrated = no rating in the problem set.

  • Unrated16
  • 800–899150
  • 900–99929
  • 1000–109937
  • 1100–119941
  • 1200–129937
  • 1300–139941

Solved by topic

Each problem counts once per tag (same as Codeforces tags). Top tags shown; remaining mass in “Other”.

  • math570
  • greedy557
  • dp463
  • constructive algorithms380
  • data structures379
  • brute force283
  • implementation

Rating changes

2019

Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

Jan
Feb
Mar
Apr
May

Submission volume

Download all years PNG

2019

Download PNG

Count of submissions per UTC day (includes every verdict).

Jan
Feb
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Apr

Recent rated rounds

When (UTC)ContestRankΔNew
2025-09-24 14:50Codeforces Round 1053 (Div. 1)16+1322884
2025-04-26 11:35Codeforces Round 1021 (Div. 1)47+322752
2025-04-19 16:35Neowise Labs Contest 1 (Codeforces Round 1018, Div. 1 + Div. 2)158-242720
2025-03-10 17:15Codeforces Round 1008 (Div. 1)131-452744
2025-01-04 17:05Hello 202560
1400–1499
48
  • 1500–159945
  • 1600–169946
  • 1700–179961
  • 1800–189962
  • 1900–199961
  • 2000–209951
  • 2100–219948
  • 2200–229956
  • 2300–239973
  • 2400–249981
  • 2500–259970
  • 2600–269964
  • 2700–279956
  • 2800–289957
  • 2900–299959
  • 3000–309972
  • 3100–319950
  • 3200–329950
  • 3300–339942
  • 3400–349924
  • 3500–359929
  • 282
  • trees213
  • graphs205
  • sortings195
  • binary search184
  • dfs and similar180
  • combinatorics167
  • number theory158
  • bitmasks138
  • two pointers106
  • strings99
  • divide and conquer86
  • dsu73
  • probabilities59
  • shortest paths56
  • games50
  • interactive49
  • geometry39
  • flows37
  • hashing34
  • matrices32
  • fft22
  • Other (9 tags)84
  • Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2020

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2021

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2022

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2023

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2024

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2025

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    2026

    Sum of rating deltas on each UTC day (GitHub-style weeks, Sunday top).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
    Nov
    Dec

    Green: rating up · red: rating down · intensity: |Δ| tiers (<50, 50–99, 100+). One square may combine multiple rated contests on the same UTC day.

    May
    Jun
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    Aug
    Sep
    Oct
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    Dec

    LessMore (max 5/day in 2019)

    2020

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
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    LessMore (max 23/day in 2020)

    2021

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
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    LessMore (max 33/day in 2021)

    2022

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
    Feb
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    May
    Jun
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    Sep
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    LessMore (max 37/day in 2022)

    2023

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
    Feb
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    May
    Jun
    Jul
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    LessMore (max 37/day in 2023)

    2024

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
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    Dec

    LessMore (max 52/day in 2024)

    2025

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
    Aug
    Sep
    Oct
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    Dec

    LessMore (max 39/day in 2025)

    2026

    Download PNG

    Count of submissions per UTC day (includes every verdict).

    Jan
    Feb
    Mar
    Apr
    May
    Jun
    Jul
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    Sep
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    Dec

    LessMore (max 3/day in 2026)

    +56
    2789
    2024-12-19 17:35Codeforces Global Round 2864+542733
    2024-11-09 17:35Refact.ai Match 1 (Codeforces Round 985)62+572679
    2024-10-27 17:35Codeforces Global Round 2732+1572622
    2024-09-27 16:05Codeforces Round 975 (Div. 1)369-552465
    2024-08-30 17:05Codeforces Round 969 (Div. 1)197-92520
    2024-04-30 17:05Codeforces Round 942 (Div. 1)371-732529
    2024-04-27 16:35Codeforces Round 941 (Div. 1)307-732602