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Commit 291363b

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Updated tasks 49-79
1 parent 4f82bb4 commit 291363b

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18 files changed

+144
-138
lines changed

18 files changed

+144
-138
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‎README.md

Lines changed: 22 additions & 22 deletions
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‎src/main/java/g0001_0100/s0049_group_anagrams/Solution.java

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Original file line numberDiff line numberDiff line change
@@ -2,24 +2,28 @@
22

33
// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Array #String #Hash_Table #Sorting
44
// #Data_Structure_II_Day_8_String #Programming_Skills_II_Day_11 #Udemy_Strings
5-
// #Big_O_Time_O(n*k_log_k)_Space_O(n) #2023_08_11_Time_6_ms_(92.28%)_Space_46.4_MB_(98.50%)
5+
// #Big_O_Time_O(n*k_log_k)_Space_O(n) #2024_11_11_Time_6_ms_(97.61%)_Space_47.7_MB_(69.56%)
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77
import java.util.ArrayList;
8-
import java.util.Arrays;
98
import java.util.HashMap;
109
import java.util.List;
1110
import java.util.Map;
1211

12+
@SuppressWarnings("java:S3824")
1313
public class Solution {
1414
public List<List<String>> groupAnagrams(String[] strs) {
15-
Map<String, List<String>> hm = new HashMap<>();
16-
for (String s : strs) {
17-
char[] ch = s.toCharArray();
18-
Arrays.sort(ch);
19-
String temp = new String(ch);
20-
hm.computeIfAbsent(temp, k -> new ArrayList<>());
21-
hm.get(temp).add(s);
15+
Map<String, List<String>> anagrams = new HashMap<>();
16+
for (String word : strs) {
17+
char[] freq = new char[26];
18+
for (char c : word.toCharArray()) {
19+
freq[c - 'a']++;
20+
}
21+
String keyString = new String(freq);
22+
if (!anagrams.containsKey(keyString)) {
23+
anagrams.put(keyString, new ArrayList<>());
24+
}
25+
anagrams.get(keyString).add(word);
2226
}
23-
return (new ArrayList<>(hm.values()));
27+
return new ArrayList<>(anagrams.values());
2428
}
2529
}
Lines changed: 42 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -1,50 +1,62 @@
11
package g0001_0100.s0051_n_queens;
22

33
// #Hard #Top_100_Liked_Questions #Array #Backtracking #Big_O_Time_O(N!)_Space_O(N)
4-
// #2023_08_11_Time_1_ms_(100.00%)_Space_43.6_MB_(97.17%)
4+
// #2024_11_11_Time_1_ms_(99.77%)_Space_44.8_MB_(61.16%)
55

66
import java.util.ArrayList;
7-
import java.util.Arrays;
7+
import java.util.LinkedList;
88
import java.util.List;
99

1010
public class Solution {
1111
public List<List<String>> solveNQueens(int n) {
12-
boolean[] pos = new boolean[n + 2 * n - 1 + 2 * n - 1];
13-
int[] pos2 = new int[n];
14-
List<List<String>> ans = new ArrayList<>();
15-
helper(n, 0, pos, pos2, ans);
16-
return ans;
12+
char[][] board = new char[n][n];
13+
for (int i = 0; i < n; i++) {
14+
for (int j = 0; j < n; j++) {
15+
board[i][j] = '.';
16+
}
17+
}
18+
List<List<String>> res = new ArrayList<>();
19+
int[] leftRow = new int[n];
20+
int[] upperDiagonal = new int[2 * n - 1];
21+
int[] lowerDiagonal = new int[2 * n - 1];
22+
solve(0, board, res, leftRow, lowerDiagonal, upperDiagonal);
23+
return res;
1724
}
1825

19-
private void helper(int n, int row, boolean[] pos, int[] pos2, List<List<String>> ans) {
20-
if (row == n) {
21-
construct(n, pos2, ans);
26+
void solve(
27+
int col,
28+
char[][] board,
29+
List<List<String>> res,
30+
int[] leftRow,
31+
int[] lowerDiagonal,
32+
int[] upperDiagonal) {
33+
if (col == board.length) {
34+
res.add(construct(board));
2235
return;
2336
}
24-
for (int i = 0; i < n; i++) {
25-
int index = n + 2 * n - 1 + n - 1 + i - row;
26-
if (pos[i] || pos[n + i + row] || pos[index]) {
27-
continue;
37+
for (int row = 0; row < board.length; row++) {
38+
if (leftRow[row] == 0
39+
&& lowerDiagonal[row + col] == 0
40+
&& upperDiagonal[board.length - 1 + col - row] == 0) {
41+
board[row][col] = 'Q';
42+
leftRow[row] = 1;
43+
lowerDiagonal[row + col] = 1;
44+
upperDiagonal[board.length - 1 + col - row] = 1;
45+
solve(col + 1, board, res, leftRow, lowerDiagonal, upperDiagonal);
46+
board[row][col] = '.';
47+
leftRow[row] = 0;
48+
lowerDiagonal[row + col] = 0;
49+
upperDiagonal[board.length - 1 + col - row] = 0;
2850
}
29-
pos[i] = true;
30-
pos[n + i + row] = true;
31-
pos[index] = true;
32-
pos2[row] = i;
33-
helper(n, row + 1, pos, pos2, ans);
34-
pos[i] = false;
35-
pos[n + i + row] = false;
36-
pos[index] = false;
3751
}
3852
}
3953

40-
private void construct(int n, int[] pos, List<List<String>> ans) {
41-
List<String> sol = new ArrayList<>();
42-
for (int r = 0; r < n; r++) {
43-
char[] queenRow = new char[n];
44-
Arrays.fill(queenRow, '.');
45-
queenRow[pos[r]] = 'Q';
46-
sol.add(new String(queenRow));
54+
List<String> construct(char[][] board) {
55+
List<String> res = new LinkedList<>();
56+
for (char[] chars : board) {
57+
String s = new String(chars);
58+
res.add(s);
4759
}
48-
ans.add(sol);
60+
returnres;
4961
}
5062
}

‎src/main/java/g0001_0100/s0053_maximum_subarray/Solution.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Array #Dynamic_Programming
44
// #Divide_and_Conquer #Data_Structure_I_Day_1_Array #Dynamic_Programming_I_Day_5
55
// #Udemy_Famous_Algorithm #Big_O_Time_O(n)_Space_O(1)
6-
// #2023_08_11_Time_1_ms_(100.00%)_Space_57.7_MB_(90.58%)
6+
// #2024_11_11_Time_1_ms_(99.32%)_Space_56.9_MB_(54.82%)
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88
public class Solution {
99
public int maxSubArray(int[] nums) {

‎src/main/java/g0001_0100/s0055_jump_game/Solution.java

Lines changed: 12 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -2,41 +2,22 @@
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33
// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Array #Dynamic_Programming #Greedy
44
// #Algorithm_II_Day_12_Dynamic_Programming #Dynamic_Programming_I_Day_4 #Udemy_Arrays
5-
// #Big_O_Time_O(n)_Space_O(1) #2023_08_11_Time_2_ms_(79.47%)_Space_44.8_MB_(22.14%)
5+
// #Big_O_Time_O(n)_Space_O(1) #2024_11_11_Time_1_ms_(100.00%)_Space_45.6_MB_(44.48%)
66

77
public class Solution {
88
public boolean canJump(int[] nums) {
9-
int sz = nums.length;
10-
// we set 1 so it won't break on the first iteration
11-
int tmp = 1;
12-
for (int i = 0; i < sz; i++) {
13-
// we always deduct tmp for every iteration
14-
tmp--;
15-
if (tmp < 0) {
16-
// if from previous iteration tmp is already 0, it will be <0 here
17-
// leading to false value
18-
return false;
19-
}
20-
// we get the maximum value because this value is supposed
21-
// to be our iterator, if both values are 0, then the next
22-
// iteration we will return false
23-
// if either both or one of them are not 0 then we will keep doing this and check.
24-
25-
// We can stop the whole iteration with this condition. without this condition the code
26-
// runs in 2ms 79.6%, adding this condition improves the performance into 1ms 100%
27-
// because if the test case jump value is quite large, instead of just iterate, we can
28-
// just check using this condition
29-
// example: [10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] -> we can just jump to the end without
30-
// iterating whole array
31-
tmp = Math.max(tmp, nums[i]);
32-
if (i + tmp >= sz - 1) {
33-
return true;
9+
if (nums.length == 1) {
10+
return true;
11+
}
12+
if (nums[0] == 0) {
13+
return false;
14+
}
15+
int fin = nums.length - 1;
16+
for (int i = nums.length - 2; i >= 0; i--) {
17+
if ((nums[i] + i) >= fin) {
18+
fin = i;
3419
}
3520
}
36-
// we can just return true at the end, because if tmp is 0 on previous
37-
// iteration,
38-
// even though the next iteration index is the last one, it will return false under the
39-
// tmp<0 condition
40-
return true;
21+
return fin == 0;
4122
}
4223
}

‎src/main/java/g0001_0100/s0056_merge_intervals/Solution.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@
22

33
// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Array #Sorting
44
// #Data_Structure_II_Day_2_Array #Level_2_Day_17_Interval #Udemy_2D_Arrays/Matrix
5-
// #Big_O_Time_O(n_log_n)_Space_O(n) #2023_08_11_Time_8_ms_(96.27%)_Space_45.2_MB_(90.13%)
5+
// #Big_O_Time_O(n_log_n)_Space_O(n) #2024_11_11_Time_7_ms_(98.37%)_Space_46.8_MB_(11.43%)
66

77
import java.util.ArrayList;
88
import java.util.Arrays;

‎src/main/java/g0001_0100/s0062_unique_paths/Solution.java

Lines changed: 1 addition & 1 deletion
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// #Medium #Top_100_Liked_Questions #Top_Interview_Questions #Dynamic_Programming #Math
44
// #Combinatorics #Algorithm_II_Day_13_Dynamic_Programming #Dynamic_Programming_I_Day_15
55
// #Level_1_Day_11_Dynamic_Programming #Big_O_Time_O(m*n)_Space_O(m*n)
6-
// #2023_08_11_Time_0_ms_(100.00%)_Space_39.2_MB_(67.74%)
6+
// #2024_11_11_Time_0_ms_(100.00%)_Space_40.7_MB_(12.56%)
77

88
public class Solution {
99
public int uniquePaths(int m, int n) {

‎src/main/java/g0001_0100/s0064_minimum_path_sum/Solution.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,7 +2,7 @@
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33
// #Medium #Top_100_Liked_Questions #Array #Dynamic_Programming #Matrix
44
// #Dynamic_Programming_I_Day_16 #Udemy_Dynamic_Programming #Big_O_Time_O(m*n)_Space_O(m*n)
5-
// #2023_08_11_Time_0_ms_(100.00%)_Space_44_MB_(58.56%)
5+
// #2024_11_11_Time_1_ms_(99.73%)_Space_47.5_MB_(44.29%)
66

77
public class Solution {
88
public int minPathSum(int[][] grid) {

‎src/main/java/g0001_0100/s0070_climbing_stairs/Solution.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
// #Easy #Top_100_Liked_Questions #Top_Interview_Questions #Dynamic_Programming #Math #Memoization
44
// #Algorithm_I_Day_12_Dynamic_Programming #Dynamic_Programming_I_Day_2
55
// #Level_1_Day_10_Dynamic_Programming #Udemy_Dynamic_Programming #Big_O_Time_O(n)_Space_O(n)
6-
// #2023_08_11_Time_0_ms_(100.00%)_Space_39.2_MB_(71.51%)
6+
// #2024_11_11_Time_0_ms_(100.00%)_Space_40.3_MB_(41.06%)
77

88
public class Solution {
99
public int climbStairs(int n) {

‎src/main/java/g0001_0100/s0072_edit_distance/Solution.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
// #Medium #Top_100_Liked_Questions #String #Dynamic_Programming
44
// #Algorithm_II_Day_18_Dynamic_Programming #Dynamic_Programming_I_Day_19
55
// #Udemy_Dynamic_Programming #Big_O_Time_O(n^2)_Space_O(n2)
6-
// #2023_08_11_Time_4_ms_(90.13%)_Space_41.8_MB_(99.78%)
6+
// #2024_11_11_Time_3_ms_(97.19%)_Space_43.2_MB_(98.23%)
77

88
@SuppressWarnings("java:S2234")
99
public class Solution {

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