si-yao

class Solution {
    public int firstMissingPositive(int[] nums) {
        for (int i = 0; i < nums.length; ++i) {
            if (nums[i] == i + 1) {
                continue;
            }
            int n = nums[i];
            nums[i] = -1;
            while (n > 0 && n <= nums.length && nums[n - 1] != n) {
                int t = nums[n - 1];

si-yao

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {

si-yao

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) {
 *         val = x;
 *         next = null;
 *     }
 * }

si-yao

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode deleteDuplicates(ListNode head) {

si-yao

// https://leetcode.com/problems/score-after-flipping-matrix/description/
// Solution: Greedy.
// It is always good to make first column all 1s, because it is the most significant bit.
// And for other columns, flip if it gives larger result.
// Correctness: We only need to prove it is optimal for 2-columns matrix.
// Though I don't havr formal proof, we can think about any counter cases: 
// is there a case that for a row starting with 0, and we don't flip the row?
// O(R*C) time.
import java.util.*;
class Solution {

si-yao

package leetcode.repeatedStringMatch;

/**
 * Created by siyao on 9/30/17.
 * https://leetcode.com/contest/leetcode-weekly-contest-52/problems/repeated-string-match/
 * Solution:
 * There are just few cases. Then at some point of repeating, if B is still not a substring,
 * then we can just stop. So the key is to find the "point", t and t + 1.
 *
 * Thinking:

si-yao

package leetcode.longestUnivaluePath;

import ds.*;

/**
 * Created by siyao on 9/30/17.
 * https://leetcode.com/contest/leetcode-weekly-contest-52/problems/longest-univalue-path/
 * Solution:
 * This does not sound like an easy level question.
 * It is not easy to come up with the correct induction or sub-problem.

si-yao

{
    "name": "Amour",
    "url": "http://www.metacritic.com/movie/amour",
    "rlsdate": "2012-12-19",
    "score": "94",
    "summary": "Georges and Anne are in their eighties. They are cultivated, retired music teachers. Their daughter, who is also a musician, lives abroad with her family. One day, Anne has an attack. The couple's...",
    "rating": "PG-13",
    "cast": "Emmanuelle Riva, Isabelle Huppert, Jean-Louis Trintignant",
    "genre": "Drama, Romance",
    "avguserscore": "8.0",

si-yao

{  
   "name":"A Girl Walks Home Alone at Night",
   "url":"http://www.metacritic.com/movie/a-girl-walks-home-alone-at-night",
   "rlsdate":"2014-11-21",
   "score":"81",
   "summary":"In the Iranian ghost-town Bad City, a place that reeks of death and loneliness, the townspeople are unaware they are being stalked by a lonesome vampire.",
   "rating":"Not Rated",
   "cast":"",
   "genre":"Thriller, Horror, Romance",
   "avguserscore":"7.2",

si-yao

{
    "rc": [
        {
            "name": "The Babadook",
            "url": "http://www.metacritic.com/movie/the-babadook",
            "rlsdate": "2014-11-28",
            "score": "86",
            "summary": "Six years after the violent death of her husband, Amelia (Essie Davis) is at a loss. She struggles to discipline her ‘out of control’ 6 year-old, Samuel (Noah Wiseman), a son she finds impossible...",
            "rating": "Not Rated",
            "cast": "Barbara West, Daniel Henshall, Essie Davis, Hayley McElhinney, Noah Wiseman",