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POJ Tools

We use the Peking University Online Judge for training. We try to build a classification to ease our problem selection.
  • We rank difficulty by: (1) trivial, (2) easy, (3) normal, (4) difficult, or (5) insane.
  • We rank whether it is interesting by: (1) bad, (2) poor, (3) standard, (4) nice, or (5) excellent.
  • Some common classifications include (1) ad hoc, (2) greedy, (3) recursive, (4) dynamic programming, (5) math, (6) simulation, and (7) graph.
Feel free to add your own opinion on any problem. We encourage you to set your school name to HKU, so that we can see our progress together.

ID Title Classification
1000 A+B Problem trivial, nice (because easy to accept XD), ad hoc - Ho Leung
1003 Hangover trivial, standard, ad hoc - Ho Leung
1004 Financial Management trivial, standard, ad hoc - Ho Leung
1005 I Think I Need a Houseboat trivial, standard, ad hoc - Ho Leung
1007 DNA Sorting trivial, standard, ad hoc - Ho Leung
1012 Joseph normal, nice, ad hoc, simulation - Ho Leung
1014 Dividing normal, nice, dynamic programming - Ho Leung
1163 The Triangle easy, standard, dynamic programming - Ho Leung
1207 The 3n + 1 problem easy, standard, simulation - Ho Leung
1316 Self Numbers easy, standard, dynamic programming - Ho Leung
1338 Ugly Numbers easy, standard, STL, math - Ho Leung
2000 Gold Coins trivial, standard, ad hoc, math - Ho Leung
2231 Moo Volume easy, standard, ad hoc, math, big integer - Ho Leung
2247 Humble Numbers easy, poor (need to know how English counts number), STL, math - Ho Leung
2367 Genealogical tree easy, standard, graph, topological sort - Ho Leung
2386 Lake Counting easy, standard, recursive, flood fill - Ho Leung
2390 Bank Interest trivial, standard, ad hoc, math - Ho Leung
2719 Faulty Odometer easy, nice, ad hoc, math - Ho Leung
3032 Card Trick trivial, standard, ad hoc - Ho Leung
3273 Monthly Expense easy, standard, ad hoc, greedy - Ho Leung
3601 Tower of Hanoi insane, nice, recursive, hanoi, math - Ho Leung
3671 Dining Cows easy, standard, ad hoc - Ho Leung

Below is another list copied from http://old.blog.edu.cn/user2/gemenhao/archives/2007/1920814.shtml.

ID Title Classification
1474 Go to problem geometry
1000 Go to problem ad hoc
1003 Go to problem ad hoc
1004 Go to problem ad hoc
1005 Go to problem ad hoc
1008 Go to problem ad hoc
1023 Go to problem ad hoc
1045 Go to problem ad hoc
1046 Go to problem ad hoc
1047 Go to problem ad hoc
1079 Go to problem ad hoc
1102 Go to problem ad hoc
1126 Go to problem ad hoc
1140 Go to problem ad hoc
1207 Go to problem ad hoc
1218 Go to problem ad hoc
1220 Go to problem ad hoc
1289 Go to problem ad hoc
1306 Go to problem ad hoc
1316 Go to problem ad hoc
1326 Go to problem ad hoc
1423 Go to problem ad hoc
1450 Go to problem ad hoc
1477 Go to problem ad hoc
1488 Go to problem ad hoc
1491 Go to problem ad hoc
1493 Go to problem ad hoc
1517 Go to problem ad hoc
1519 Go to problem ad hoc
1528 Go to problem ad hoc
1552 Go to problem ad hoc
1565 Go to problem ad hoc
1583 Go to problem ad hoc
1628 Go to problem ad hoc
1635 Go to problem ad hoc
1657 Go to problem ad hoc
1658 Go to problem ad hoc
1663 Go to problem ad hoc
1665 Go to problem ad hoc
1759 Go to problem ad hoc
1775 Go to problem ad hoc
1781 Go to problem ad hoc
1809 Go to problem ad hoc
1859 Go to problem ad hoc
1868 Go to problem ad hoc
1936 Go to problem ad hoc
1942 Go to problem ad hoc
1969 Go to problem ad hoc
2000 Go to problem ad hoc
2006 Go to problem ad hoc
2013 Go to problem ad hoc
2015 Go to problem ad hoc
2017 Go to problem ad hoc
2027 Go to problem ad hoc
2083 Go to problem ad hoc
2105 Go to problem ad hoc
2109 Go to problem ad hoc
2126 Go to problem ad hoc
2136 Go to problem ad hoc
2140 Go to problem ad hoc
2141 Go to problem ad hoc
2144 Go to problem ad hoc
2159 Go to problem ad hoc
2190 Go to problem ad hoc
2196 Go to problem ad hoc
2231 Go to problem ad hoc
2249 Go to problem ad hoc
2262 Go to problem ad hoc
2272 Go to problem ad hoc
2301 Go to problem ad hoc
2305 Go to problem ad hoc
2309 Go to problem ad hoc
2316 Go to problem ad hoc
2321 Go to problem ad hoc
2328 Go to problem ad hoc
2330 Go to problem ad hoc
2350 Go to problem ad hoc
2351 Go to problem ad hoc
2379 Go to problem ad hoc
2380 Go to problem ad hoc
2390 Go to problem ad hoc
2403 Go to problem ad hoc
2419 Go to problem ad hoc
1131 Go to problem algebra
1707 Go to problem algebra
1125 Go to problem all pairs shortest paths
1375 Go to problem analytical geometry
1473 Go to problem analytical geometry
2098 Go to problem analytical geometry
2242 Go to problem analytical geometry
1001 Go to problem arbitrary precision calculation
1354 Go to problem arbitrary precision calculation
1454 Go to problem arbitrary precision calculation
1503 Go to problem arbitrary precision calculation
2389 Go to problem arbitrary precision calculation
2413 Go to problem arbitrary precision calculation
2240 Go to problem Bellman-Ford algorithm
1195 Go to problem binary indexed tree
1330 Go to problem binary search
2418 Go to problem binary search tree
1466 Go to problem bipartite graph matching
1087 Go to problem bipartite graph matching or maximum flow
2018 Go to problem bisection and dynamic programming
1505 Go to problem bisection and greedy
1434 Go to problem bisection method
2155 Go to problem bit operation or binary indexed tree
1111 Go to problem breadth first search
1562 Go to problem breadth first search
1724 Go to problem breadth first search
1753 Go to problem breadth first search
1915 Go to problem breadth first search
1924 Go to problem breadth first search
2225 Go to problem breadth first search
2243 Go to problem breadth first search
2251 Go to problem breadth first search
2312 Go to problem breadth first search
2386 Go to problem breadth first search
2415 Go to problem breadth first search
2426 Go to problem breadth first search
2435 Go to problem breadth first search
1209 Go to problem calendar
2080 Go to problem calendar
2210 Go to problem calendar
1031 Go to problem computational geometry
1127 Go to problem computational geometry
1648 Go to problem computational geometry
1654 Go to problem computational geometry
1675 Go to problem computational geometry
1912 Go to problem computational geometry
2099 Go to problem computational geometry
2150 Go to problem computational geometry
2318 Go to problem computational geometry
2398 Go to problem computational geometry
2423 Go to problem computational geometry
1032 Go to problem construction
1147 Go to problem construction
1148 Go to problem construction
1702 Go to problem construction
1844 Go to problem construction
1898 Go to problem construction
1906 Go to problem construction
2085 Go to problem construction
2319 Go to problem construction
2356 Go to problem construction
2402 Go to problem construction
1426 Go to problem construction or breadth first search
1606 Go to problem construction or breadth first search
1113 Go to problem convex hull
2187 Go to problem convex hull and enumeration
1010 Go to problem depth first search
1011 Go to problem depth first search
1022 Go to problem depth first search
1054 Go to problem depth first search
1118 Go to problem depth first search
1144 Go to problem depth first search
1190 Go to problem depth first search
1564 Go to problem depth first search
1655 Go to problem depth first search
1904 Go to problem depth first search
1980 Go to problem depth first search
2184 Go to problem depth first search
2186 Go to problem depth first search
2362 Go to problem depth first search
2378 Go to problem depth first search
2438 Go to problem depth first search
1151 Go to problem discretization and union of intervals or segment tree
1182 Go to problem disjoint sets
1291 Go to problem disjoint sets
1703 Go to problem disjoint sets
1984 Go to problem disjoint sets
2021 Go to problem disjoint sets
2236 Go to problem disjoint sets
2371 Go to problem divide and conquer
2388 Go to problem divide and conquer
1014 Go to problem dynamic programming
1015 Go to problem dynamic programming
1018 Go to problem dynamic programming
1036 Go to problem dynamic programming
1038 Go to problem dynamic programming
1050 Go to problem dynamic programming
1088 Go to problem dynamic programming
1093 Go to problem dynamic programming
1156 Go to problem dynamic programming
1157 Go to problem dynamic programming
1159 Go to problem dynamic programming
1160 Go to problem dynamic programming
1163 Go to problem dynamic programming
1170 Go to problem dynamic programming
1191 Go to problem dynamic programming
1221 Go to problem dynamic programming
1338 Go to problem dynamic programming
1458 Go to problem dynamic programming
1579 Go to problem dynamic programming
1631 Go to problem dynamic programming
1651 Go to problem dynamic programming
1661 Go to problem dynamic programming
1664 Go to problem dynamic programming
1678 Go to problem dynamic programming
1685 Go to problem dynamic programming
1722 Go to problem dynamic programming
1732 Go to problem dynamic programming
1745 Go to problem dynamic programming
1821 Go to problem dynamic programming
1909 Go to problem dynamic programming
1923 Go to problem dynamic programming
1925 Go to problem dynamic programming
1953 Go to problem dynamic programming
2033 Go to problem dynamic programming
2133 Go to problem dynamic programming
2151 Go to problem dynamic programming
2181 Go to problem dynamic programming
2229 Go to problem dynamic programming
2247 Go to problem dynamic programming
2250 Go to problem dynamic programming
2342 Go to problem dynamic programming
2353 Go to problem dynamic programming
2355 Go to problem dynamic programming
2385 Go to problem dynamic programming
2393 Go to problem dynamic programming
2397 Go to problem dynamic programming
2414 Go to problem dynamic programming
2430 Go to problem dynamic programming
2439 Go to problem dynamic programming
2441 Go to problem dynamic programming
2442 Go to problem dynamic programming
2084 Go to problem dynamic programming and arbitrary precision calculation
1387 Go to problem dynamic programming and enumeration
1322 Go to problem dynamic programming or generating function
1012 Go to problem enumeration
1013 Go to problem enumeration
1142 Go to problem enumeration
1171 Go to problem enumeration
1183 Go to problem enumeration
1318 Go to problem enumeration
1411 Go to problem enumeration
1543 Go to problem enumeration
1647 Go to problem enumeration
1650 Go to problem enumeration
1828 Go to problem enumeration
1916 Go to problem enumeration
1930 Go to problem enumeration
2078 Go to problem enumeration
2100 Go to problem enumeration
2191 Go to problem enumeration
2245 Go to problem enumeration
2326 Go to problem enumeration
2346 Go to problem enumeration
2363 Go to problem enumeration
2381 Go to problem enumeration
2436 Go to problem enumeration
2444 Go to problem enumeration
1267 Go to problem enumeration and bisection
1129 Go to problem enumeration and depth first search
1186 Go to problem enumeration and hash table
1348 Go to problem enumration
1472 Go to problem expression evaluation
2106 Go to problem expression evaluation
2246 Go to problem expression evaluation
2269 Go to problem expression evaluation
2234 Go to problem game theory
2348 Go to problem game theory
2425 Go to problem game theory
1799 Go to problem geometry
1927 Go to problem geometry
1939 Go to problem geometry
1940 Go to problem geometry
2007 Go to problem geometry
2208 Go to problem geometry
2276 Go to problem geometry
2365 Go to problem geometry
2405 Go to problem geometry
1981 Go to problem geometry and enumeration
1090 Go to problem Gray code
1832 Go to problem Gray code
1017 Go to problem greedy
1042 Go to problem greedy
1083 Go to problem greedy
1230 Go to problem greedy
1328 Go to problem greedy
1456 Go to problem greedy
1862 Go to problem greedy
1922 Go to problem greedy
2054 Go to problem greedy
2082 Go to problem greedy
2209 Go to problem greedy
2291 Go to problem greedy
2313 Go to problem greedy
2325 Go to problem greedy
2370 Go to problem greedy
2376 Go to problem greedy
2431 Go to problem greedy
2433 Go to problem greedy
2437 Go to problem greedy
1405 Go to problem greedy and arbitrary precision calculation
1659 Go to problem greedy and construction
1026 Go to problem group theory
1033 Go to problem group theory
1286 Go to problem group theory
1674 Go to problem group theory
2369 Go to problem group theory
2409 Go to problem group theory
2366 Go to problem hash table or binary search
1521 Go to problem Huffman tree
1742 Go to problem knapsack
2392 Go to problem knapsack
1538 Go to problem Lagrangian interpolation
2344 Go to problem linear algebra and greedy
1462 Go to problem linear systems
1914 Go to problem linear systems
2440 Go to problem matrix algebra
1149 Go to problem maximum flow
1273 Go to problem maximum flow
1459 Go to problem maximum flow
2125 Go to problem maximum flow and minimum cut
2377 Go to problem maximum spanning tree
1258 Go to problem minimum spanning tree
1679 Go to problem minimum spanning tree
1861 Go to problem minimum spanning tree
2421 Go to problem minimum spanning tree
1166 Go to problem modular systems
1222 Go to problem modular systems
1681 Go to problem modular systems
2345 Go to problem modular systems
1905 Go to problem Newton's iteration
2420 Go to problem Newton's iteration
2299 Go to problem number of inversions
1006 Go to problem number theory
1061 Go to problem number theory
1067 Go to problem number theory
1152 Go to problem number theory
1284 Go to problem number theory
1320 Go to problem number theory
1401 Go to problem number theory
1455 Go to problem number theory
1597 Go to problem number theory
1808 Go to problem number theory
1811 Go to problem number theory
1845 Go to problem number theory
1995 Go to problem number theory
2115 Go to problem number theory
2407 Go to problem number theory
2417 Go to problem number theory
2429 Go to problem number theory and enumeration
1146 Go to problem permutation
1256 Go to problem permutation
1731 Go to problem permutation
1833 Go to problem permutation
2079 Go to problem rotating calipers
2104 Go to problem search
1177 Go to problem segment tree
2182 Go to problem segment tree
2352 Go to problem segment tree or binary indexed tree
1016 Go to problem simulation
1028 Go to problem simulation
1048 Go to problem simulation
1049 Go to problem simulation
1051 Go to problem simulation
1060 Go to problem simulation
1281 Go to problem simulation
1298 Go to problem simulation
1363 Go to problem simulation
1504 Go to problem simulation
1573 Go to problem simulation
1578 Go to problem simulation
1589 Go to problem simulation
1592 Go to problem simulation
1600 Go to problem simulation
1656 Go to problem simulation
1660 Go to problem simulation
1666 Go to problem simulation
1684 Go to problem simulation
1926 Go to problem simulation
1928 Go to problem simulation
1978 Go to problem simulation
2014 Go to problem simulation
2039 Go to problem simulation
2050 Go to problem simulation
2051 Go to problem simulation
2081 Go to problem simulation
2271 Go to problem simulation
2317 Go to problem simulation
2339 Go to problem simulation
2340 Go to problem simulation
2359 Go to problem simulation
2383 Go to problem simulation
2410 Go to problem simulation
2424 Go to problem simulation
2443 Go to problem simulation
2387 Go to problem single source shortest paths
2394 Go to problem single source shortest paths
1002 Go to problem sorting
1245 Go to problem sorting
1520 Go to problem sorting
2092 Go to problem sorting
2408 Go to problem sorting
1007 Go to problem stable sorting
1572 Go to problem string manipulation
1646 Go to problem string manipulation
1917 Go to problem string manipulation
2406 Go to problem string matching
1128 Go to problem topological sorting
1785 Go to problem treap
2201 Go to problem treap
2255 Go to problem tree manipulation
1089 Go to problem union of intervals
1797 Go to problem variation of Dijkstra's shortest path algorithm
2253 Go to problem variation of Dijkstra's shortest path algorithm
2395 Go to problem variation of Dijkstra's shortest path algorithm
2254 Go to problem vector algebra
2354 Go to problem vector algebra
2412 Go to problem vector algebra
1130 Go to problem vertex connectivity
1308 Go to problem vertex connectivity
2320 Go to problem vertex connectivity





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