Problems

two sum: http://www.lintcode.com/en/problem/two-sum/

• sort + two pointers
• hashmap

3 sum: http://www.lintcode.com/en/problem/3sum/

4 sum: http://www.lintcode.com/en/problem/4sum/

k sum: http://www.lintcode.com/en/problem/k-sum/

k sum ii: http://www.lintcode.com/en/problem/k-sum-ii/

2 sum closest: http://www.lintcode.com/en/problem/two-sum-closest-to-target/

3 sum closest: http://www.lintcode.com/en/problem/3sum-closest/

partition array: http://www.lintcode.com/en/problem/partition-array/

• 两分 vs 三分

sort letter by case: http://www.lintcode.com/en/problem/sort-letters-by-case/

sort colors: http://www.lintcode.com/en/problem/sort-colors/

sort colors ii: http://www.lintcode.com/en/problem/sort-colors-ii/

interleaving positive and negative numbers: http://www.lintcode.com/en/problem/interleaving-positive-and-negative-numbers/