Codeforces数论题单

【CF 1200-1600 - 数论】(基础概念与简单计算)

• CF1328A Divisibility Problem (向上取整)
• CF1352C K-th Not Divisible by n (二分/数学推导)
• CF1360A Minimal Square (简单几何与大小判断)
• CF1294A Collecting Coins (简单整除与余数)
• CF732A Buy a Shovel (枚举/模拟)
• CF617A Elephant (贪心，步长为5)
• CF4A Watermelon (判断偶数且大于2)
• CF1370A Maximum GCD (结论题，n/2)
• CF1475A Odd Divisor (判断数是否为2的幂)
• CF1343B Balanced Array (构造)
• CF1335A Candies and Two Sisters (简单计数)
• CF492A Vanya and Cubes (模拟/公式)
• CF1353B Two Arrays And Swaps (贪心)
• CF1097A Gennady and a Card Game (简单字符串匹配)
• CF705A Hulk (字符串构造)
• CF271A Beautiful Year (枚举，判断各位数字不同)
• CF110A Nearly Lucky Number (判断幸运数字个数是否为幸运数)
• CF469A I Wanna Be the Guy (set/bool数组判断全覆盖)
• CF749A Bachgold Problem (构造，尽量用2)
• CF131A cAPS lOCK (字符串大小写转换)
• CF59A Word (字符串大小写转换)
• CF1367A Short Substrings (字符串构造)
• CF1374A Required Remainder (数学计算)
• CF1220A Cards (计数，"z"和"n"的个数)
• CF1409A Yet Another Two Integers Problem (向上取整)
• CF268A Games (暴力枚举)
• CF443A Anton and Letters (set去重)
• CF318A Even Odds (分奇偶讨论)
• CF472A Design Tutorial: Learn from Math (构造，x=4, n-4 或 x=9, n-9)
• CF1399A Remove Smallest (排序判断相邻差是否<=1)

【CF 1600-2100 - 数论】(GCD, LCM, 逆元, 筛法, 简单组合)

• CF1201C Maximum Median (二分答案 + 判断)
• CF1360E Minimal Diameter Path (构造/贪心)
• CF1473B String LCM (字符串LCM，GCD(len1, len2))
• CF1095C Powers Of Two (位运算构造)
• CF1342C Yet Another Counting Problem (周期性 + 前缀和)
• CF1294C Product of Three Numbers (暴力枚举因子)
• CF1215B The Number of Products (DP/前缀积统计正负)
• CF1359E Modular Stability (组合计数，Lucas定理)
• CF1462E Similar Arrays (组合计数 + 双指针)
• CF1420B Rock and Lever (按最高位分组计数)
• CF1333C Eugene and an array (前缀和 + map判重复)
• CF1303C Perfect Keyboard (图论构造/DFS)
• CF1406C Link Cut Centroids (树的重心性质)
• CF1395C Boboniu and String (位运算 + DP/BFS)
• CF1005D Polycarp and Divisible by 3 (DP，记录模3余数)
• CF451E Devu and Flowers (容斥原理 + 组合数求不定方程解)
• CF1312C Adding Powers (k进制分解)
• CF777D Cloud of Hashtags (字符串贪心，从后往前删)
• CF1203F1 Complete the Projects (easy version) (贪心排序)
• CF1077D Cutting Out (二分答案 + 贪心检查)
• CF1288C Two K-Subsequences (组合计数，隔板法)
• CF893C Rumor (并查集/DFS求连通块最小权值)
• CF1155D Beautiful Array (DP，最大子段和变形，可乘x)
• CF1370D Odd-Even Subsequence (二分答案 + DP/贪心检查)
• CF1354B Ternary String (双指针/滑动窗口)
• CF919D Substring (拓扑排序 + DAG上DP，判环)
• CF1253C Sweets Eating (前缀和 + DP)
• CF448C Painting Fence (分治DP)
• CF1363C Game On Leaves (博弈论，判断谁能取到重心)
• CF1166C A Tale of Two Lands (排序 + 双指针/二分)

【CF 2100-2500+ - 数论】(高级定理, 反演, 生成函数, 多项式)

• CF1097D Makoto and a Blackboard (期望DP，质因数分解)
• CF961G Partitions (斯特林数 + 组合意义)
• CF932E Team Work (组合恒等式 $k^n = \sum \binom{k}{i} i! S(n,i)$ + DP)
• CF1100F Ivan and Burgers (线性基)
• CF1305F Kuroni and the Punishment (随机化 + 素数测试 + GCD)
• CF1228E Another Filling the Grid (容斥原理 + 快速幂)
• CF1025G Company Acquisitions (博弈论/SG函数，打表找规律)
• CF1322B Present (按位考虑贡献 + 排序双指针/树状数组)
• CF1051E Vasya and Big Integers (数位DP + 字符串哈希/KMP优化转移)
• CF917D Stranger Trees (矩阵树定理 + 拉格朗日插值/高斯消元)
• CF1012C Hills (DP，状态记录前两个高度关系)
• CF840C On the Bench (DP计数 + 容斥原理，处理平方因子)
• CF1278F Cards (期望线性性 + 第二类斯特林数/组合恒等式)
• CF1188C DP on tree (点分治/树形DP + 贡献法，处理路径权值限制)
• CF1139E Maximize Mex (网络流/二分图匹配 + 贪心) - 虽然是图论，但mex常和数论性质结合
• CF1017G The Tree (树链剖分 + 线段树维护复杂信息，可能涉及数论变换)
• CF997C Sky Full of Stars (容斥原理 + 快速幂)
• CF1081E Missing Numbers (构造，a^2-b^2=(a-b)(a+b))
• CF1065F Up and Down the Tree (树形DP + 长链剖分/Dsu on tree优化)
• CF889E Mod Mod Mod (数论变换 + 数据结构优化DP)
• CF1208G Polygons (最小表示法/KMP求循环节，然后欧拉函数计数)
• CF1175F The Number of Subpermutations (分治/扫描线 + 数据结构维护区间性质)
• CF1028G Max Sum Array (交互题，五分法/多路查找)
• CF1033G Chip Game (博弈论SG函数 + 分类讨论)
• CF1007C As simple as LCM (交互题，二分/三分缩小范围)
• CF1110F Nearest Leaf (点分治/LCA + 线段树/DFS序维护路径信息)
• CF986C AND Graph (并查集/DFS，按位建图)
• CF1034C Region Separation (树上倍增 + GCD性质)
• CF923D Picking Strings (字符串哈希 + 二分/DP，处理B的个数)
• CF1098C Construct a tree (构造，贪心分配子节点)