Solve Trapping Rain Water II

silviobraendle/trapping_rain_water_ii/BUILD

@@ -0,0 +1,11 @@
+load("@rules_java//java:defs.bzl", "java_binary")
+
+package(default_visibility = ["//visibility:public"])
+
+java_binary(
+    name = "trapping_rain_water_ii",
+    srcs = glob(["*.java"]),
+    main_class = "silviobraendle.trapping_rain_water_ii.Main",
+    deps = [
+    ],
+)

silviobraendle/trapping_rain_water_ii/Main.java

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+package silviobraendle.trapping_rain_water_ii;
+
+public class Main {
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        int[][] heightMap = {
+                { 122, 120, 51, 39, 14, 63, 28, 100, 84, 37, 56, 19, 127, 93, 58, 16, 97, 78, 46, 31 },
+                { 91, 14, 51, 35, 75, 47, 30, 83, 124, 100, 8, 81, 78, 53, 28, 115, 111, 150, 80, 83 },
+                { 69, 135, 31, 76, 35, 111, 70, 75, 47, 49, 74, 126, 111, 4, 83, 17, 111, 74, 108, 141 },
+                { 56, 35, 144, 42, 62, 64, 22, 46, 109, 123, 115, 32, 96, 133, 71, 67, 136, 83, 48, 115 },
+                { 30, 31, 66, 14, 105, 116, 31, 148, 77, 94, 126, 111, 87, 140, 124, 25, 21, 84, 38, 49 },
+                { 84, 72, 128, 120, 54, 78, 67, 121, 138, 85, 63, 8, 144, 138, 68, 119, 123, 27, 6, 128 },
+                { 119, 4, 3, 118, 31, 68, 86, 32, 68, 42, 101, 72, 14, 121, 61, 133, 78, 95, 6, 15 },
+                { 99, 113, 31, 74, 119, 35, 133, 41, 43, 48, 100, 27, 45, 81, 114, 141, 128, 64, 91, 36 },
+                { 61, 91, 130, 133, 130, 91, 127, 52, 33, 41, 46, 88, 55, 71, 77, 45, 92, 49, 94, 9 },
+                { 65, 94, 148, 49, 36, 24, 89, 73, 15, 98, 104, 69, 42, 75, 49, 26, 98, 144, 82, 132 },
+                { 26, 79, 22, 45, 13, 138, 61, 126, 128, 25, 19, 25, 136, 50, 83, 145, 34, 72, 60, 25 },
+                { 35, 4, 39, 104, 63, 61, 62, 20, 53, 138, 24, 107, 138, 134, 0, 27, 53, 13, 40, 83 },
+                { 36, 83, 15, 117, 81, 101, 32, 95, 1, 44, 0, 141, 89, 14, 128, 68, 95, 2, 15, 133 },
+                { 108, 85, 57, 58, 19, 68, 141, 132, 100, 78, 101, 86, 135, 91, 15, 36, 94, 71, 139, 115 },
+                { 9, 107, 26, 13, 93, 147, 119, 124, 123, 45, 68, 53, 140, 87, 135, 34, 45, 120, 36, 127 },
+                { 44, 36, 38, 147, 48, 10, 60, 32, 51, 6, 78, 137, 1, 130, 132, 80, 17, 132, 12, 41 },
+                { 52, 77, 7, 135, 107, 134, 26, 150, 95, 76, 95, 52, 74, 23, 50, 72, 110, 4, 1, 62 },
+                { 73, 66, 132, 88, 147, 74, 51, 146, 84, 73, 87, 94, 58, 120, 52, 0, 58, 10, 41, 59 },
+                { 60, 18, 49, 101, 7, 2, 80, 147, 101, 26, 3, 9, 4, 13, 118, 54, 50, 106, 1, 75 },
+                { 77, 98, 112, 92, 55, 3, 66, 133, 18, 39, 83, 117, 12, 131, 28, 4, 116, 101, 22, 70 },
+        };
+        int answer = solution.trapRainWater(heightMap);
+        System.out.println(answer);
+    }
+}

silviobraendle/trapping_rain_water_ii/Solution.java

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+package silviobraendle.trapping_rain_water_ii;
+
+public class Solution {
+    public int trapRainWater(int[][] heightMap) {
+        int m = heightMap.length;
+        int n = heightMap[0].length;
+
+        int maxLevel = findMaxLevel(heightMap);
+
+        int waterSum = 0;
+
+        for (int level = maxLevel; level > 0; level--) {
+            boolean[][] visited = new boolean[m][n];
+            for (int i = 0; i < m; i++) {
+                findPath(i, 0, visited, heightMap, level);
+                findPath(i, n - 1, visited, heightMap, level);
+            }
+            for (int j = 1; j < n - 1; j++) {
+                findPath(0, j, visited, heightMap, level);
+                findPath(m - 1, j, visited, heightMap, level);
+            }
+
+            waterSum += sumLevel(heightMap, level, visited);
+        }
+
+        return waterSum;
+    }
+
+    private int sumLevel(int[][] heightMap, int level, boolean[][] visited) {
+        int m = heightMap.length;
+        int n = heightMap[0].length;
+
+        int levelSum = 0;
+
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                if (visited[i][j]) {
+                    continue;
+                }
+
+                if (heightMap[i][j] >= level) {
+                    continue;
+                }
+
+                levelSum++;
+            }
+        }
+        
+        return levelSum;
+    }
+
+    private void findPath(int i, int j, boolean[][] visited, int[][] heightMap, int level) {
+        int m = visited.length;
+        int n = visited[0].length;
+
+        if (!isInBounds(i, j, m, n)) {
+            return;
+        }
+
+        if (visited[i][j]) {
+            return;
+        }
+
+        if (heightMap[i][j] >= level) {
+            return;
+        }
+
+        visited[i][j] = true;
+
+        findPath(i + 1, j, visited, heightMap, level); // inc i
+        findPath(i - 1, j, visited, heightMap, level); // dec i
+        findPath(i, j + 1, visited, heightMap, level); // inc j
+        findPath(i, j - 1, visited, heightMap, level); // dec j
+    }
+
+    private boolean isInBounds(int i, int j, int m, int n) {
+        return i >= 0 && i < m && j >= 0 && j < n;
+    }
+
+    private int findMaxLevel(int[][] heightMap) {
+        int m = heightMap.length;
+        int n = heightMap[0].length;
+
+        int maxLevel = 0;
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                int value = heightMap[i][j];
+                if (value > maxLevel) {
+                    maxLevel = value;
+                }
+            }
+        }
+
+        return maxLevel;
+    }
+}