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  • paginated_contents/algorithms/1st_thousand
  • src
    • main/java/com/fishercoder/solutions/firstthousand
    • test/java/com/fishercoder/firstthousand

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Diff for: ‎paginated_contents/algorithms/1st_thousand/README.md

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| 783 | [Minimum Distance Between BST Nodes](https://leetcode.com/problems/minimum-distance-between-bst-nodes/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_783.java) | | Easy |
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| 781 | [Rabbits in Forest](https://leetcode.com/problems/rabbits-in-forest/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_781.java) | [:tv:](https://youtu.be/leiSa1i-QrI) | Medium | HashTable, Math
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| 779 | [K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_779.java) | | Medium |
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| 777 | [Swap Adjacent in LR String](https://leetcode.com/problems/swap-adjacent-in-lr-string/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_777.java) | | Medium | Two Pointers, String
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| 776 | [Split BST](https://leetcode.com/problems/split-bst/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_776.java) | | Medium | Recursion
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| 775 | [Global and Local Inversions](https://leetcode.com/problems/global-and-local-inversions/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_775.java) | | Medium | Array, Math
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| 773 | [Sliding Puzzle](https://leetcode.com/problems/sliding-puzzle/) | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/firstthousand/_773.java) | | Hard | BFS

Diff for: ‎src/main/java/com/fishercoder/solutions/firstthousand/_777.java

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package com.fishercoder.solutions.firstthousand;
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public class _777 {
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public static class Solution1 {
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public boolean canTransform(String start, String end) {
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StringBuilder sb = new StringBuilder();
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for (char c : start.toCharArray()) {
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if (c != 'X') {
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sb.append(c);
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}
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}
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String cleanedStart = sb.toString();
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sb.setLength(0);
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for (char c : end.toCharArray()) {
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if (c != 'X') {
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sb.append(c);
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}
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}
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String cleandEnd = sb.toString();
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if (!cleanedStart.equals(cleandEnd)) {
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return false;
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}
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//check R from left, check on the start string for R first
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//whenever count becomes negative, this means we encounter an R in a more left position in end string than start string
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//since R could only be moved to the right in the start string, there's no way that start string could be shifted to match end string
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//test11 illustrates this well
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int count = 0;
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for (int i = 0; i < start.length(); i++) {
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if (start.charAt(i) == 'R') {
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count++;
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}
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if (end.charAt(i) == 'R') {
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count--;
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}
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if (count < 0) {
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return false;
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}
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}
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//check L from left, but check on the end string first,
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//this means if L is in a more left index in start string than end string, it's impossible for start to match end
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//test12 illustrates this case well
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count = 0;
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for (int i = 0; i < end.length(); i++) {
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if (end.charAt(i) == 'L') {
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count++;
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}
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if (start.charAt(i) == 'L') {
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count--;
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}
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if (count < 0) {
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return false;
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}
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}
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return true;
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}
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}
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}

Diff for: ‎src/test/java/com/fishercoder/firstthousand/_777Test.java

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package com.fishercoder.firstthousand;
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import com.fishercoder.solutions.firstthousand._777;
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import org.junit.jupiter.api.BeforeEach;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.assertFalse;
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import static org.junit.jupiter.api.Assertions.assertTrue;
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public class _777Test {
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private static _777.Solution1 solution1;
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@BeforeEach
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public void setup() {
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solution1 = new _777.Solution1();
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}
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@Test
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public void test1() {
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assertTrue(solution1.canTransform("RXXLRXRXL", "XRLXXRRLX"));
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}
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@Test
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public void test2() {
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assertFalse(solution1.canTransform("X", "L"));
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}
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@Test
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public void test3() {
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assertTrue(solution1.canTransform("XXXXXLXXXX", "LXXXXXXXXX"));
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}
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@Test
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public void test4() {
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assertFalse(solution1.canTransform("LLR", "RRL"));
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}
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@Test
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public void test5() {
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assertFalse(solution1.canTransform("XXXL", "LXXR"));
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}
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@Test
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public void test6() {
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assertTrue(solution1.canTransform("RXXX", "XXXR"));
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}
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@Test
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public void test7() {
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assertTrue(solution1.canTransform("XXRXLXRXXX", "XXRLXXXXXR"));
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}
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@Test
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public void test8() {
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assertFalse(solution1.canTransform("XLLR", "LXLX"));
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}
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@Test
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public void test9() {
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assertFalse(solution1.canTransform("RXR", "XXR"));
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}
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@Test
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public void test10() {
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assertTrue(solution1.canTransform("XLXRRXXRXX", "LXXXXXXRRR"));
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}
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@Test
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public void test11() {
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assertFalse(solution1.canTransform("LXXLXRLXXL", "XLLXRXLXLX"));
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}
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@Test
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public void test12() {
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assertFalse(solution1.canTransform("XXXXXLXXXLXXXX", "XXLXXXXXXXXLXX"));
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}
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}

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