add 1059

Author: fishercoder1534

Diff for: paginated_contents/algorithms/2nd_thousand/README.md

@@ -430,6 +430,7 @@
 | 1062 | [Longest Repeating Substring](https://leetcode.com/problems/longest-repeating-substring/)                                                                                                    | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1062.java)                                                                                       |                                                     | Medium                           | String, Binary Search, DP, Rolling Hash, Suffix Array, Hash Function |
 | 1061 | [Lexicographically Smallest Equivalent String](https://leetcode.com/problems/lexicographically-smallest-equivalent-string/)                                                                  | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1061.java)                                                                                       | [:tv:](https://youtu.be/HvCaMw58_94)                | Medium                           | Union Find                                                           
 | 1060 | [Missing Element in Sorted Array](https://leetcode.com/problems/missing-element-in-sorted-array/)                                                                                                                            | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1060.java)                                                                                       |                                                     | Medium                           ||Binary Search
+| 1059 | [All Paths from Source Lead to Destination](https://leetcode.com/problems/all-paths-from-source-lead-to-destination/)                                                                                                                                  | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1059.java)                                                                                       |                                                     | Medium                           |DFS
 | 1057 | [Campus Bikes](https://leetcode.com/problems/campus-bikes/)                                                                                                                                  | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1057.java)                                                                                       |                                                     | Medium                           ||Greedy, Sort
 | 1056 | [Confusing Number](https://leetcode.com/problems/confusing-number/)                                                                                                                          | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1056.java)                                                                                       |                                                     | Easy                             ||
 | 1055 | [Fixed Point](https://leetcode.com/problems/fixed-point/)                                                                                                                                    | [Solution](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/secondthousand/_1055.java)                                                                                       |                                                     | Easy                             ||

Diff for: src/main/java/com/fishercoder/solutions/secondthousand/_1059.java

@@ -0,0 +1,60 @@
+package com.fishercoder.solutions.secondthousand;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class _1059 {
+    public static class Solution1 {
+        /**
+         * Credit: https://leetcode.com/problems/all-paths-from-source-lead-to-destination/editorial/
+         * A very powerful algorithm, three colors to DFS a tree/graph.
+         */
+        enum Color {
+            WHITE,
+            GRAY,
+            BLACK
+        }
+
+        public boolean leadsToDestination(int n, int[][] edges, int source, int destination) {
+            List<Integer>[] graph = buildGraph(n, edges);
+            Color[] colors = new Color[n];
+            for (int i = 0; i < n; i++) {
+                colors[i] = Color.WHITE;
+            }
+            return leadsToDest(graph, colors, source, destination);
+        }
+
+        private boolean leadsToDest(List<Integer>[] graph, Color[] colors, int node, int destination) {
+            //if it's not WHITE, then it should be BLACK, otherwise, there's a circle
+            if (colors[node] != Color.WHITE) {
+                return colors[node] == Color.BLACK;
+            }
+            //if this is a leaf node, then it should be destination, otherwise, it's a dead end and we return false
+            if (graph[node].size() == 0) {
+                return node == destination;
+            }
+
+            //now, we start processing this node and mark it as GRAY
+            colors[node] = Color.GRAY;
+            for (int neighbor : graph[node]) {
+                if (!leadsToDest(graph, colors, neighbor, destination)) {
+                    return false;
+                }
+            }
+            //recursive processing is done, we mark it as BLACK
+            colors[node] = Color.BLACK;
+            return true;
+        }
+
+        private static List<Integer>[] buildGraph(int n, int[][] edges) {
+            List<Integer>[] graph = new ArrayList[n];
+            for (int i = 0; i < n; i++) {
+                graph[i] = new ArrayList<>();
+            }
+            for (int[] edge : edges) {
+                graph[edge[0]].add(edge[1]);
+            }
+            return graph;
+        }
+    }
+}