Merge branch 'week10'

Author: spring0913

Diff for: week10/Leetcode_(Path Sum III).java

@@ -0,0 +1,28 @@
+class Solution {
+    private int count;
+    private int targetSum;
+    private long[] sum;
+
+    public int pathSum(TreeNode root, int _targetSum) {
+        targetSum = _targetSum;
+        sum = new long[1001];
+        dfs(root, 1);
+        return count;
+    }
+
+    public void dfs(TreeNode node, int depth) {
+        if(node == null) {
+            return;
+        }
+
+        sum[depth] = sum[depth-1] + node.val;
+        for(int i=depth-1; i>=0; i--) {
+            if(sum[depth] - sum[i] == targetSum) {
+                count++;
+            }
+        }
+
+        dfs(node.left, depth+1);
+        dfs(node.right, depth+1);
+    }
+}

Diff for: week10/Programmers_12946(하노이의 탑).java

@@ -0,0 +1,23 @@
+import java.util.*;
+
+class Solution {
+
+    private List<int[]> arr;
+
+    public int[][] solution(int n) {
+        arr = new ArrayList<>();
+        hanoi(1, 2, 3, n);
+        int[][] answer = arr.stream().toArray(int[][]::new);
+        return answer;
+    }
+
+    public void hanoi(int from, int mid, int to, int n) {
+        if(n == 0) {
+            return;
+        }
+
+        hanoi(from, to, mid, n-1);
+        arr.add(new int[]{from, to});
+        hanoi(mid, from, to, n-1);
+    }
+}

Diff for: week10/Programmers_43163(단어 변환).java

@@ -0,0 +1,43 @@
+class Solution {
+
+    private String[] words;
+    private boolean[] visited;
+    private String target;
+    private int answer;
+
+    public int solution(String begin, String _target, String[] _words) {
+        words = _words;
+        target = _target;
+        visited = new boolean[words.length];
+        answer = Integer.MAX_VALUE;
+        dfs(begin, 0, 0);
+        return (answer == Integer.MAX_VALUE) ? 0 : answer;
+    }
+
+    public void dfs(String now, int step, int count) {
+        if(now.equals(target)) {
+            answer = Math.min(answer, count);
+            return;
+        }
+        if(step == words.length) {
+            return;
+        }
+
+        for(int i=0; i<words.length; i++) {
+            if(!visited[i] && check(now, words[i])) {
+                visited[i] = true;
+                dfs(words[i], step+1, count+1);
+                visited[i] = false;
+            }
+        }
+    }
+
+    public boolean check(String s1, String s2) {
+        int count = 0;
+        int len = s1.length();
+        for(int i=0; i<len; i++) {
+            count += (s1.charAt(i) == s2.charAt(i)) ? 1 : 0;
+        }
+        return (count == len-1);
+    }
+}

Diff for: week10/Programmers_43164(여행경로).java

@@ -0,0 +1,48 @@
+import java.util.*;
+
+class Solution {
+    private String[][] tickets;
+    private boolean[] visited;
+    private List<List<String>> pathList;
+
+    public String[] solution(String[][] _tickets) {
+        tickets = _tickets;
+        visited = new boolean[tickets.length];
+        pathList = new ArrayList<>();
+        List<String> path = new ArrayList<>();
+        path.add("ICN");
+        path = dfs(path, "ICN");
+        Collections.sort(pathList, (o1, o2) -> {
+            for(int i=0; i<o1.size(); i++) {
+                String s1 = o1.get(i);
+                String s2 = o2.get(i);
+                if(!s1.equals(s2)) {
+                    return s1.compareTo(s2);
+                }
+            }
+            return 0;
+        });
+        String[] answer = pathList.get(0).stream().toArray(String[]::new);
+        return answer;
+    }
+
+    public List<String> dfs(List<String> path, String now) {
+        if(path.size() == tickets.length+1) {
+            pathList.add(new ArrayList<String>(path));
+            return path;
+        }
+
+        for(int i=0; i<tickets.length; i++) {
+            String v1 = tickets[i][0];
+            String v2 = tickets[i][1];
+            if(v1.equals(now) && !visited[i]) {
+                path.add(v2);
+                visited[i] = true;
+                dfs(path, v2);
+                visited[i] = false;
+                path.remove(path.size()-1);
+            }
+        }
+        return path;
+    }
+}