5.leetcode/src/Q17.java

@@ -1,30 +0,0 @@
-package com.fanxb.common;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-public class Q17 {
-    private Set<String> res = new HashSet<>();
-    private StringBuilder stringBuilder = new StringBuilder();
-    private String[] map = new String[]{"", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
-
-    public List<String> letterCombinations(String digits) {
-        if (digits.isEmpty()) return new ArrayList<>();
-        dfs(digits.length(), digits, 0);
-        return new ArrayList<>(res);
-    }
-
-    private void dfs(int size, String digits, int i) {
-        if (stringBuilder.length() == size) {
-            res.add(stringBuilder.toString());
-            return;
-        }
-        for (char c : map[digits.charAt(i) - '0'].toCharArray()) {
-            stringBuilder.append(c);
-            dfs(size, digits, i + 1);
-            stringBuilder.deleteCharAt(stringBuilder.length() - 1);
-        }
-    }
-}

5.leetcode/src/com/fanxb/common/Q22.java

@@ -1,51 +0,0 @@
-package com.fanxb.common;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-public class Q22 {
-    Set<String> ans;
-    //左括号个数
-    int lCount;
-    //右括号个数
-    int rCount;
-    StringBuilder temp;
-
-    public List<String> generateParenthesis(int n) {
-        ans = new HashSet<>();
-        lCount = 0;
-        rCount = 0;
-        temp = new StringBuilder();
-        dfs(n, 2 * n);
-        return new ArrayList<>(ans);
-    }
-
-    private void dfs(int n, int total) {
-        if (temp.length() == total) {
-            ans.add(temp.toString());
-            return;
-        }
-        if (lCount < n) {
-            lCount++;
-            temp.append('(');
-            dfs(n, total);
-            lCount--;
-            temp.deleteCharAt(temp.length() - 1);
-        }
-        if (rCount < lCount) {
-            rCount++;
-            temp.append(')');
-            dfs(n, total);
-            rCount--;
-            temp.deleteCharAt(temp.length() - 1);
-        }
-    }
-
-    public static void main(String[] args) {
-        long start = System.currentTimeMillis();
-        System.out.println(new Q22().generateParenthesis(8));
-        System.out.println(System.currentTimeMillis() - start);
-    }
-}

5.leetcode/src/com/fanxb/common/Q39.java

@@ -33,35 +33,6 @@ public class Q39 {
         }
     }
 
-    private class NewSolution {
-        private List<List<Integer>> res;
-        private List<Integer> temp;
-        private int sum;
-
-        public List<List<Integer>> combinationSum(int[] candidates, int target) {
-            res = new ArrayList<>();
-            temp = new ArrayList<>();
-            sum = 0;
-            dfs(candidates, target, 0);
-            return res;
-        }
-
-        private void dfs(int[] candidates, int target, int cur) {
-            if (sum > target) return;
-            if (sum == target) {
-                res.add(new ArrayList<>(temp));
-                return;
-            }
-            for (int i = cur; i < candidates.length; i++) {
-                temp.add(candidates[i]);
-                sum += candidates[i];
-                dfs(candidates, target, i);
-                sum -= candidates[i];
-                temp.remove(temp.size() - 1);
-            }
-        }
-    }
-
     public static void main(String[] args) {
         new Q39().combinationSum(new int[]{2, 3, 5}, 8).forEach(System.out::println);
     }

5.leetcode/src/com/fanxb/common/Q46.java

@@ -1,7 +1,6 @@
 package com.fanxb.common;
 
 import java.util.ArrayList;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Stack;
 
@@ -44,37 +43,6 @@ public class Q46 {
         }
     }
 
-    private static class NewSolution {
-        private List<List<Integer>> res;
-        private List<Integer> temp;
-        private boolean[] cache;
-
-        public List<List<Integer>> permute(int[] nums) {
-            res = new LinkedList<>();
-            temp = new ArrayList<>(nums.length);
-            cache = new boolean[nums.length];
-            dfs(nums, nums.length);
-            return res;
-        }
-
-        private void dfs(int[] nums, int length) {
-            if (temp.size() == nums.length) {
-                res.add(new ArrayList<>(temp));
-                return;
-            }
-            for (int i = 0; i < length; i++) {
-                if (!cache[i]) {
-                    temp.add(nums[i]);
-                    cache[i] = true;
-                    dfs(nums, length);
-                    cache[i] = false;
-                    temp.remove(temp.size() - 1);
-                }
-            }
-        }
-    }
-
-
     public static void main(String[] args) {
         System.out.println(new Q46().permute(new int[]{1, 1, 2}));
     }

5.leetcode/src/com/fanxb/common/Q52.java

@@ -1,40 +0,0 @@
-package com.fanxb.common;
-
-import java.util.ArrayList;
-import java.util.List;
-
-public class Q52 {
-    private List<Integer[]> state;
-    //记录列上的皇后
-    private boolean[] col;
-    private int res;
-
-
-    public int totalNQueens(int n) {
-        state = new ArrayList<>(n);
-        col = new boolean[n];
-        res = 0;
-        dfs(n, 0);
-        return res;
-    }
-
-    private void dfs(int n, int cur) {
-        if (state.size() == n) {
-            res++;
-            return;
-        }
-        for (int i = 0; i < n; i++) {
-            //当前行或者当前列已经放了，那么跳过
-            if (col[i]) continue;
-            //判断斜线上有没有存在的皇后，判断方法：主对角线行减列的差值相等，次对角线的行加列值相等
-            int val1 = cur - i, val2 = cur + i;
-            if (state.stream().anyMatch(item -> item[0] - item[1] == val1 || item[0] + item[1] == val2)) continue;
-            state.add(new Integer[]{cur, i});
-            col[i] = true;
-            //往下一行放
-            dfs(n, cur + 1);
-            state.remove(state.size() - 1);
-            col[i] = false;
-        }
-    }
-}

5.leetcode/src/com/fanxb/common/Q77.java

@@ -1,31 +0,0 @@
-package com.fanxb.common;
-
-import java.util.ArrayList;
-import java.util.LinkedList;
-import java.util.List;
-
-public class Q77 {
-    public List<List<Integer>> combine(int n, int k) {
-        List<List<Integer>> ans = new LinkedList<>();
-        List<Integer> temp = new ArrayList<>(k);
-        dfs(ans, temp, n, k, 1);
-        return ans;
-    }
-
-    private void dfs(List<List<Integer>> ans, List<Integer> temp, int n, int k, int cur) {
-        if (temp.size() == k) {
-            ans.add(new ArrayList<>(temp));
-            return;
-        }
-        for (int i = cur; i <= n; i++) {
-            temp.add(i);
-            dfs(ans, temp, n, k, i + 1);
-            temp.remove(temp.size() - 1);
-        }
-    }
-
-    public static void main(String[] args) {
-        new Q77().combine(4, 2);
-    }
-
-}

5.leetcode/src/com/fanxb/common/Q79.java

@@ -1,29 +0,0 @@
-package com.fanxb.common;
-
-public class Q79 {
-    private int[][] step = new int[][]{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
-
-    public boolean exist(char[][] board, String word) {
-        char[] chars = word.toCharArray();
-        int m = board.length, n = board[0].length;
-        for (int i = 0; i < m; i++) {
-            for (int j = 0; j < n; j++) {
-                if (dfs(board, chars, 0, i, j, m, n)) return true;
-            }
-        }
-        return false;
-    }
-
-    private boolean dfs(char[][] board, char[] word, int k, int x, int y, int m, int n) {
-        if (word[k] != board[x][y]) return false;
-        if (k == word.length - 1) return true;
-        board[x][y] = ' ';
-        for (int[] item : step) {
-            int x1 = x + item[0], y1 = y + item[1];
-            if (x1 < 0 || x1 >= m || y1 < 0 || y1 >= n || board[x1][y1] == ' ') continue;
-            if (dfs(board, word, k + 1, x1, y1, m, n)) return true;
-        }
-        board[x][y] = word[k];
-        return false;
-    }
-}