Educational Codeforces Round 174 (Div. 2) 题目讲解 ABCDE (CF2069)

芋饼饭

合集 · 题目讲解 (117)

  1. 14:40
    [题解] CF1918D. Blocking Elements (4连招学以致用的一天)
  2. 11:51
    [题解] ABC338G. evall （一道有趣的计数题）
  3. 17:41
    题目讲解 LeetCode 3187. Peaks in Array / Codeforces Round 953 E. Computing Machine
  4. 45:19
    Codeforces Round 957 (Div. 3) 题目讲解 (ABCDEFG)
  5. 37:12
    Codeforces Round 959 (Div. 1+2) 题目讲解 (ABCDE)
  6. 52:06
    Codeforces Round 961 (Div. 2) 题目讲解 (CF1995 ABCD)
  7. 40:18
    CF1997F. Chips on a Line 题目讲解 (dp接dp)
  8. 55:19
    Codeforces Round 963 (Div. 2) 题目讲解 (ABCDF1)
  9. 47:03
    Educational Codeforces Round 168 (Div. 2) 题目讲解 (CF1997 ABCDE)
  10. 29:02
    Codeforces Round 964 (Div. 4) 题目讲解 (ABCDEFG1G2)
  11. 1:03:42
    Codeforces Round 965 (Div. 2) 题目讲解 (ABCDE1)
  12. 25:05
    CF1996G. Penacony 题目讲解 (Codeforces Round 962 G)
  13. 52:30
    Codeforces Round 966 (Div. 3) 题目讲解 (ABCDEFH)
  14. 36:19
    CF2000G. Call During the Journey 题目讲解 (Codeforces Round 966 G) 一个思路两种实现
  15. 54:43
    Codeforces Round 967 (Div. 2) 题目讲解 (ABCDE1)
  16. 38:48
    Codeforces Round 968 (Div. 2) 题目讲解 (ABCD1D2)
  17. 41:45
    Codeforces Round 970 (Div. 3) 题目讲解 (ABCDEFGH)
  18. 45:23
    Codeforces Round 971 (Div. 4) 题目讲解 (ABCDEFG1G2)
  19. 1:21:21
    Codeforces Round 974 (Div. 3) 题目讲解 (ABCDEFGH)
  20. 1:43:51
    Codeforces Round 977 (Div. 2) 题目讲解 (ABC1C2DE1E2)
  21. 23:09
    LeetCode Biweekly Contest 141 题目讲解 (ABCD)
  22. 1:31:21
    Educational Codeforces Round 170 (Div. 2) 题目讲解 (ABCDEF)
  23. 1:47:37
    Codeforces Round 980 (Div. 2) 题目讲解 (ABCDEF)
  24. 1:11:48
    Codeforces Round 979 (Div. 2) 题目讲解 (ABCDE) CF2030
  25. 1:03:21
    Codeforces Round 981 (Div. 3) 题目讲解 (ABCDEFG) CF2033
  26. 1:02:00
    Codeforces Round 982 (Div. 2) 题目讲解 (ABCD1D2) CF2027
  27. 57:25
    Educational Codeforces Round 171 (Div. 2) 题目讲解 ABCDE (CF2026)
  28. 1:08:38
    Codeforces Round 984 (Div. 3) 题目讲解 ABCDEFG (CF2036)
  29. 1:10:26
    Refact.ai Match 1 (Codeforces Round 985) 题目讲解 ABCDE (CF2029)
  30. 1:25:36
    Codeforces Round 986 (Div. 2) 题目讲解 ABCDE (CF2028)
  31. 53:46
    Codeforces Round 988 (Div. 3) 题目讲解 ABCDEGF (CF2037)
  32. 1:08:35
    2024-2025 ICPC, NERC, Southern and Volga Russian Regional 题目讲解 NJCALKGB (CF2038)
  33. 47:42
    Codeforces Round 989 Div.1+2 题目讲解 ABCDE (CF2034) Rayan Programming Contest 2024
  34. 46:52
    Codeforces Round 990 (Div. 2) 题目讲解 ABCDE (CF2047)
  35. 42:42
    Educational Codeforces Round 172 (Div. 2) 题目讲解 ABCD (CF2042)
  36. 45:44
    Codeforces Round 991 (Div. 3) 题目讲解 ABCDEFG (CF2050)
  37. 39:12
    LeetCode Biweekly Contest 145 题目讲解 (ABCD)
  38. 1:06:17
    Codeforces Round 992 (Div. 2) 题目讲解 ABCDE (CF2040)
  39. 49:49
    Codeforces Round 993 (Div. 4) 题目讲解 ABCDEFG1G2H (CF2044)
  40. 47:37
    Codeforces Global Round 28 题目讲解 ABCDE (CF2048)
  41. 50:08
    LeetCode Biweekly Contest 146 题目讲解 (BCD)
  42. 1:03:24
    Codeforces Round 994 (Div. 2) 题目讲解 ABCDE (CF2049)
  43. 47:44
    Codeforces Round 995 (Div. 3) 题目讲解 ABCDEFG (CF2051)
  44. 48:16
    Educational Codeforces Round 173 (Div. 2) 题目讲解 ABCDE (CF2043)
  45. 1:03:40
    Codeforces Good Bye 2024: 2025 is NEAR 题目讲解 ABCDE (CF2053)
  46. 1:07:36
    Codeforces Hello 2025 题目讲解 ABCDE1E2 (CF2057)
  47. 1:18:52
    Codeforces Round 996 (Div. 2) 题目讲解 ABCD (CF2055)
  48. 58:07
    Codeforces Round 998 (Div. 3) 题目讲解 ABCDEFG (CF2060)
  49. 1:08:43
    Codeforces Round 997 (Div. 2) 题目讲解 ABCDE (CF2056)
  50. 1:07:34
    IAEPC Preliminary Contest (Codeforces Round 999, Div. 1+2) 题目讲解 ABCDEF1 (CF2061)
  51. 1:13:27
    Codeforces Round 1000 (Div. 2) 题目讲解 ABCDEF1 (CF2063)
  52. 1:01:21
    Codeforces Round 1003 (Div. 4) 题目讲解 BCDEFGH (CF2065)
  53. 1:55:04
    Codeforces Round 1005 (Div. 2) 题目讲解 ABCDE (CF2064)
  54. 46:11
    Educational Codeforces Round 174 (Div. 2) 题目讲解 ABCDE (CF2069)
  55. 1:04:38
    Codeforces Round 1006 (Div. 3) 题目讲解 ABCDEFG (CF2072)
  56. 51:24
    Educational Codeforces Round 175 (Rated for Div. 2) 题目讲解 ABCD (CF2070)
  57. 1:01:55
    Codeforces Round 1007 (Div. 2) 题目讲解 ABCD1D2 (CF2071)
  58. 1:17:29
    Codeforces Round 1008 (Div. 2) 题目讲解 ABCDEF (CF2078)
  59. 1:21:45
    Codeforces Round 1009 (Div. 3) 题目讲解 ABCDEF (CF2074)
  60. 1:14:44
    Codeforces Round 1010 (Div. 2) 题目讲解 ABCD (CF2082)
  61. 38:03
    Educational Codeforces Round 176 (Div. 2) 题目讲解 ABCD (CF2075)
  62. 36:25
    Codeforces Round 1011 (Div. 2) 题目讲解 ABCDE (CF2085)
  63. 1:10:37
    Codeforces Round 1012 (Div. 2) 题目讲解 ABCDE1 (CF2090)
  64. 1:12:21
    Codeforces Round 1013 (Div. 3) 题目讲解 ABCDEF (CF2091)
  65. 42:20
    Codeforces Round 1014 (Div. 2) 题目讲解 ABCDE (CF2092)
  66. 1:29:02
    Teza Round 1 (Codeforces Round 1015, Div 1 + 2) 题目讲解 ABCD (CF2084)
  67. 37:14
    Codeforces Round 1016 (Div. 3) 题目讲解 ABCDEF (CF2093)
  68. 45:11
    Educational Codeforces Round 177 (Div. 2) 题目讲解 BCDE (CF2086)
  69. 39:51
    Codeforces Round 1017 (Div. 4) 题目讲解 GH (CF2094)
  70. 56:18
    Neowise Labs Contest 1 (Codeforces Round 1018 Div. 1+2) 题目讲解 ABCDE (CF2096)
  71. 48:10
    Codeforces Round 1019 (Div. 2) 题目讲解 ABCE (CF2103)
  72. 1:12:36
    Codeforces Round 1020 (Div. 3) 题目讲解 CDEFG1G2 (CF2106)
  73. 1:16:41
    Codeforces Round 1023 (Div. 2) 题目讲解 ABCDF1 (CF2107)
  74. 1:26:44
    Codeforces Round 1021 (Div. 2) 题目讲解 ABCDE (CF2098)
  75. 55:26
    Codeforces Round 1024 (Div. 2) 题目讲解 ABCDE (CF2102)
  76. 1:00:07
    Codeforces Round 1025 (Div. 2) 题目讲解 ABC1C2C3DE (CF2109)
  77. 34:59
    Codeforces Round 1026 (Div. 2) 题目讲解 ABCDE (CF2110)
  78. 2:02:49
    Codeforces Round 1027 (Div. 3) 实况+讲解 (CF2114)
  79. 2:11:45
    Educational Codeforces Round 179 (Rated for Div. 2) 实况+讲解 ABCDE (CF2111)
  80. 42:55
    Codeforces Round 1029 (Div. 3) 题目讲解 ABCDEFG (CF2117)
  81. 50:09
    Codeforces Round 1030 (Div. 2) 题目讲解 ABCD1D2 (CF2118)
  82. 1:09:52
    Codeforces Round 1031 (Div. 2) 题目讲解 ABCDF (CF2113)
  83. 1:17:13
    Codeforces Round 1032 (Div. 3) 题目讲解 ABCDEFGH (CF2121)
  84. 46:25
    Codeforces Round 1033 (Div. 2) and CodeNite 2025 题目讲解 ABCDE (CF2120)
  85. 49:01
    Codeforces Round 1034 (Div. 3) 题目讲解 ABCDEFG (CF2123)
  86. 1:13:15
    Codeforces Round 1035 (Div. 2) 题目讲解 ABCDE (CF2119)
  87. 34:41
    Codeforces Round 1037 (Div. 3) 题目讲解 ABCDEF (CF2126)
  88. 1:09:21
    Order Capital Round 1 (Codeforces Round 1038, Div. 1+2) 题目讲解 ABCDE (CF2122)
  89. 52:37
    Educational Codeforces Round 181 (Div. 2) 题目讲解 ABCDE (CF2125)
  90. 1:09:16
    Codeforces Round 1042 (Div. 3) 题目讲解 A~H (CF2131)
  91. 1:04:22
    Codeforces Round 1047 (Div. 3) 题目讲解 A~G (CF2137)
  92. 54:00
    Codeforces Round 1050 (Div. 4) 题目讲解 B~G (CF2148)
  93. 1:21:45
    Codeforces Round 1051 (Div. 2) 题目讲解 A~E (CF2143)
  94. 44:45
    Codeforces Round 1052 (Div. 2) 题目讲解 A~E (CF2146)
  95. 1:21:09
    Codeforces Round 1053 (Div. 2) 题目讲解 A~G1 (CF2151)
  96. 1:24:47
    Codeforces Round 1054 (Div. 3) 题目讲解 A~G (CF2149)
  97. 45:02
    AtCoder Beginner Contest 425 题目讲解 AC~G (ABC425)
  98. 59:28
    Educational Codeforces Round 183 (Div. 2) 题目讲解 C~F (CF2145)
  99. 0:13
    Codeforces Round 1056 拼好饭题解
  100. 1:12:52
    Codeforces Round 1055 (Div. 1 + 2) 题目讲解 A~G (CF2152)
  101. 53:36
    Codeforces Round 1057 (Div. 2) 题目讲解 B~F (CF2153)
  102. 40:50
    AtCoder Beginner Contest 427 题目讲解 A~F (ABC427)
  103. 1:24:27
    Codeforces Round 1058 (Div. 2) 题目讲解 A~G2 (CF2160)
  104. 46:01
    Codeforces Round 1059 (Div. 3) 题目讲解 A~G (CF2162)
  105. 0:18
    ABC428 和 CF Round 1060
  106. 1:40:38
    Codeforces Round 1062 (Div. 4) 实况+题目讲解 A~G (CF2167)
  107. 1:07:21
    Codeforces Global Round 30 (Div. 1 + Div. 2) 题目讲解 A~F2 (CF2164)
  108. 54:24
    Codeforces Round 1064 (Div. 1) B. Marble Council (CF2165B/CF2166D) 讲解
  109. 1:10:29
    Codeforces Round 1065 (Div. 3) 题目讲解 C~H (CF2171)
  110. 32:54
    Codeforces Round 1066 (Div. 1 + 2) D. Billion Players (CF2157D) 讲解
  111. 21:16
    Codeforces Round 1066 (Div. 1 + 2) E. Adjusting Drones (CF2157E) 讲解
  112. 46:24
    Educational Codeforces Round 185 (Div. 2) 题目讲解 B~F (CF2170)
  113. 1:21:33
    Codeforces Round 1082 (Div. 2) 题目讲解 （CF2202）
  114. 1:13:52
    Educational Codeforces Round 188 (Div. 2) 题目讲解 (CF2205)
  115. 1:11:23
    Codeforces Round 1087 (Div. 2) 题目讲解 (CF2209)
  116. 1:20:46
    Codeforces Round 1089 (Div. 2) 题目讲解 (CF2210)
  117. 33:54
    Educational Codeforces Round 191 (Div. 2) 题目讲解 (CF2233)
Description 
B:
考虑grid的奇偶性
C:
#DPBasic 动态规划基础 https://www.bilibili.com/video/BV1PF4m1M7sH
D:
分情况讨论，贪心
E:
分情况讨论，贪心

Comments

请各位叫我去学习 2025-02-27

up C题的dp太强了,蒻暨写组合数O(n方)写半天还WA了[doge_金箍] 这是不是说dp和组合数是不是有关系(还在组合数[生气]) f【i】 定义: 以第 i 个 2 结尾的 1 2 ...2 序列的数量,前面的所有序列都可以加上第i个2来组成新的序列,这种情况 f【i 】 <- f【i - 1】,除此之外,也可以选择不加上第 i 个 2,这样同样是 f【di - 1】 个序列,也就是原先的,这样f【i】 又得到一个 f【i - 1】,这种情况即使 第 i 个数不是 2 也是由 f【i - 1】转移过来 1. 所有1 - (i - 1)中可以组成的所有合法序列 1 2 ... 2 加上第 i 个 2, 新增加了 f【i - 1】个序列 2. 原先所有序列,不加上第 i 个 2,即原来的 f【i - 1】 3. 如果这个 2 是 序列 1 2 ... 2 的 第 2 个 2,那么每出现一个 2, 都可以和前面所有的1 来组成 1 2 ... 2中的第二个2,这也是产生序列的情况

♥ 5 ↩ 1

coord_axis 2025-02-19

C题我把一些非Python的负数取模给hack了[doge]

♥ 4 ↩ 3

KagaMiku39 2025-03-12

这个grid的奇偶性，或者用另一个说法就是矩阵构成的图没有奇环所以符合二分图判定，最小能分割成的不联通子集是2

♥ 2

我恋上我左手 2025-02-19

upup能把C题怎么想到用dp的思路或技巧简单讲一下吗[给心心][给心心]我昨天死在那想着枚举每对1和3之间2的个数，但怎么想都是n方的复杂度[笑哭][笑哭]

♥ 1 ↩ 9

-Kyoll- 2025-02-19

太快了，给力[打call][打call]

♥ 1

黎明下的琉璃鸟 2025-02-19

好快的速度，昨天10比的赛今天就出题解了[打call]

♥ 1

Ricardo_Z_Liu 2025-02-26

讲得太好了，upF题有吗

↩ 1

小萌新也有大梦想 2025-02-23

老师下次能分段吗[给心心]

↩ 1

_____柠檬_____ 2025-02-21

upup，C题当第i个位置为2时为什么还要加上前面1的个数啊[辣眼睛]

↩ 1

幻顾 2025-02-20

[星星眼]

Happiness_3 2025-02-19

支持支持！！！

冷白雨 2025-02-19

[打call][打call][打call]

平静的海_CalmSea 2025-02-23

c题讲的好好[打call]虽然可能我太菜了动态规划还不太会，但是这个思路长见识了，动态规划还能这样用来计算子序列

平原旅人 2025-02-23

UP讲的真好[给心心]支持喵

凌辰zz 2025-02-21

跪求1004(div2)

凌辰zz 2025-02-21

‍你用的是哪个软件的画图板 可以推荐一下吗

↩ 1

凌辰zz 2025-02-20

b题的图两次可以说一下吗

↩ 1

曙翔sx 2025-02-19

[星星眼][星星眼]

凌辰zz 2025-02-19

好的 明天有的学了

グアイカ 2025-02-19

阴间时间周二比赛，缺席了[doge]

↩ 1