add 942

Author: fishercoder1534

README.md

@@ -43,6 +43,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |961|[N-Repeated Element in Size 2N Array](https://leetcode.com/problems/n-repeated-element-in-size-2n-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_961.java) | O(n) | O(1) | |Easy|
 |953|[Verifying an Alien Dictionary](https://leetcode.com/problems/verifying-an-alien-dictionary/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_953.java) | O(1) | O(1) | |Easy|
 |944|[Delete Columns to Make Sorted](https://leetcode.com/problems/delete-columns-to-make-sorted/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_944.java) | O(n) | O(1) | |Easy|
+|942|[DI String Match](https://leetcode.com/problems/di-string-match/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_942.java) | O(n) | O(n) | |Easy|
 |941|[Valid Mountain Array](https://leetcode.com/problems/valid-mountain-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_941.java) | O(n) | O(1) | |Easy|
 |938|[Range Sum of BST](https://leetcode.com/problems/range-sum-of-bst/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_938.java) | O(n) | O(n) | |Medium| BST, recursion, DFS
 |937|[Reorder Log Files](https://leetcode.com/problems/reorder-log-files/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_937.java) | O(n) | O(n) | |Easy|

src/main/java/com/fishercoder/solutions/_942.java

@@ -0,0 +1,52 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayDeque;
+import java.util.Queue;
+
+/**
+ * 942. DI String Match
+ *
+ * Given a string S that only contains "I" (increase) or "D" (decrease), let N = S.length.
+ *
+ * Return any permutation A of [0, 1, ..., N] such that for all i = 0, ..., N-1:
+ *
+ * If S[i] == "I", then A[i] < A[i+1]
+ * If S[i] == "D", then A[i] > A[i+1]
+ *
+ * Example 1:
+ * Input: "IDID"
+ * Output: [0,4,1,3,2]
+ *
+ * Example 2:
+ * Input: "III"
+ * Output: [0,1,2,3]
+ *
+ * Example 3:
+ * Input: "DDI"
+ * Output: [3,2,0,1]
+ *
+ * Note:
+ * 1 <= S.length <= 10000
+ * S only contains characters "I" or "D".
+ */
+public class _942 {
+  public static class Solution1 {
+    public int[] diStringMatch(String S) {
+      Queue<Integer> deque = new ArrayDeque<>();
+      for (int i = 0; i <= S.length(); i++) {
+        deque.add(i);
+      }
+      int[] result = new int[S.length() + 1];
+      for (int i = 0; i <= S.length(); i++) {
+        if (i == S.length()) {
+          result[i] = ((ArrayDeque<Integer>) deque).pollLast();
+        } else if (S.charAt(i) == 'I') {
+          result[i] = ((ArrayDeque<Integer>) deque).pollFirst();
+        } else {
+          result[i] = ((ArrayDeque<Integer>) deque).pollLast();
+        }
+      }
+      return result;
+    }
+  }
+}

src/test/java/com/fishercoder/_942Test.java

@@ -0,0 +1,30 @@
+package com.fishercoder;
+
+import com.fishercoder.common.utils.CommonUtils;
+import com.fishercoder.solutions._942;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class _942Test {
+  private static _942.Solution1 solution1;
+
+  @BeforeClass
+  public static void setup() {
+    solution1 = new _942.Solution1();
+  }
+
+  @Test
+  public void test1() {
+    CommonUtils.printArray(solution1.diStringMatch("IDID"));
+  }
+
+  @Test
+  public void test2() {
+    CommonUtils.printArray(solution1.diStringMatch("III"));
+  }
+
+  @Test
+  public void test3() {
+    CommonUtils.printArray(solution1.diStringMatch("DDI"));
+  }
+}