2016 年 12月 3 日随笔档案 - neverlandly

2016年12月3日

摘要： Time Complexity will be O(n) because the "start" and "end" points will only move from left to right once. Sliding Window: Use a count to denote the di 阅读全文

posted @ 2016-12-03 13:14 neverlandly 阅读(1403) 评论(0) 推荐(0)

Leetcode: Pacific Atlantic Water Flow

摘要：这题考点在于需要设置两个visited数组 Two Queue and add all the Pacific border to one queue; Atlantic border to another queue. Keep a visited matrix for each queue. I 阅读全文

posted @ 2016-12-03 12:05 neverlandly 阅读(799) 评论(0) 推荐(0)

Leetcode: Partition Equal Subset Sum

摘要： Backpack problem: dp[i][j] means if the first i elements can sum up to value j dp[i][j] = dp[i-1][j] || (j>=nums[i-1] && dp[i-1][j-nums[i-1]]) the res 阅读全文

posted @ 2016-12-03 10:29 neverlandly 阅读(309) 评论(0) 推荐(0)

Leetcode: Third Maximum Number

摘要： My Solution: Highest votes in discussion 阅读全文

posted @ 2016-12-03 06:22 neverlandly 阅读(374) 评论(0) 推荐(0)

Leetcode: Arithmetic Slices

摘要： A slice (P, Q)其实就是从P到Q的序列，（P，Q）是arithmetic slice要求是等差数列且至少有三个数，问array里面有多少个这样的（P, Q）这道题难点在于想到用DP，一旦想到用DP，就迎刃而解 dp[i]表示以i结束的slice有多少个阅读全文

posted @ 2016-12-03 05:12 neverlandly 阅读(372) 评论(0) 推荐(0)

Leetcode: Trapping Rain Water II

摘要： The above image represents the elevation map [[1,4,3,1,3,2],[3,2,1,3,2,4],[2,3,3,2,3,1]] before the rain. After the rain, water are trapped between th 阅读全文

posted @ 2016-12-03 03:16 neverlandly 阅读(558) 评论(0) 推荐(0)

Leetcode: Remove K Digits

摘要： Greedy + Stack: 用一个栈维护最后要留存下来的digits 需要注意的是：如果遍历到string的某个char, string后面的char数刚刚好能填满这个栈，那么即使这个char比栈顶还要小，也不出栈，直接入栈最后要删除leading 0 用char[]实现栈，思路一样，要快很多阅读全文

posted @ 2016-12-03 00:24 neverlandly 阅读(439) 评论(0) 推荐(0)