leetcode-2021.3.13 (#71)

* running-sum-of-1d-array

* shuffle-the-array

* richest-customer-wealth

* number-of-good-pairs

* Formatted with Google Java Formatter

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: realDuYuanChao

.gitignore

@@ -2,6 +2,7 @@
 /build/
 .idea/
 target
+*.iml
 
 # Ignore Gradle GUI config
 gradle-app.setting

src/main/java/com/examplehub/leetcode/easy/NumberOfGoodPairs.java

@@ -0,0 +1,16 @@
+package com.examplehub.leetcode.easy;
+
+/** https://leetcode.com/problems/number-of-good-pairs/ */
+public class NumberOfGoodPairs {
+  public static int solution1(int[] nums) {
+    int goodPairs = 0;
+    for (int i = 0; i < nums.length; ++i) {
+      for (int j = i + 1; j < nums.length; j++) {
+        if (nums[i] == nums[j]) {
+          goodPairs++;
+        }
+      }
+    }
+    return goodPairs;
+  }
+}

src/main/java/com/examplehub/leetcode/easy/RichestCustomerWealth.java

@@ -0,0 +1,17 @@
+package com.examplehub.leetcode.easy;
+
+import com.examplehub.maths.SumOfArray;
+
+/** https://leetcode.com/problems/richest-customer-wealth/ */
+public class RichestCustomerWealth {
+  public static int solution1(int[][] accounts) {
+    int max = SumOfArray.sum(accounts[0]);
+    for (int i = 1; i < accounts.length; ++i) {
+      int temp = SumOfArray.sum(accounts[i]);
+      if (temp > max) {
+        max = temp;
+      }
+    }
+    return max;
+  }
+}

src/main/java/com/examplehub/leetcode/easy/RunningSumOf1dArray.java

@@ -0,0 +1,11 @@
+package com.examplehub.leetcode.easy;
+
+/** https://leetcode.com/problems/running-sum-of-1d-array/ */
+public class RunningSumOf1dArray {
+  public static int[] solution1(int[] nums) {
+    for (int i = 1; i < nums.length; ++i) {
+      nums[i] += nums[i - 1];
+    }
+    return nums;
+  }
+}

src/main/java/com/examplehub/leetcode/easy/ShuffleTheArray.java

@@ -0,0 +1,15 @@
+package com.examplehub.leetcode.easy;
+
+/** https://leetcode.com/problems/shuffle-the-array/ */
+public class ShuffleTheArray {
+  public static int[] solution1(int[] nums, int n) {
+    int[] result = new int[nums.length];
+    int index = 0;
+    for (int i = 0, j = n; i < n; i++, j++) {
+      result[index++] = nums[i];
+      result[index++] = nums[j];
+    }
+    System.arraycopy(result, 0, nums, 0, result.length);
+    return nums;
+  }
+}

src/test/java/com/examplehub/leetcode/easy/NumberOfGoodPairsTest.java

@@ -0,0 +1,16 @@
+package com.examplehub.leetcode.easy;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class NumberOfGoodPairsTest {
+  @Test
+  void testSolution1() {
+    int[] numbers = new int[] {1, 2, 3, 1, 1, 3};
+    assertEquals(4, NumberOfGoodPairs.solution1(numbers));
+
+    numbers = new int[] {1, 1, 1, 1};
+    assertEquals(6, NumberOfGoodPairs.solution1(numbers));
+  }
+}

src/test/java/com/examplehub/leetcode/easy/RichestCustomerWealthTest.java

@@ -0,0 +1,25 @@
+package com.examplehub.leetcode.easy;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class RichestCustomerWealthTest {
+  @Test
+  void test() {
+    int[][] account =
+        new int[][] {
+          {1, 2, 3},
+          {3, 2, 1}
+        };
+    assertEquals(RichestCustomerWealth.solution1(account), 6);
+
+    account =
+        new int[][] {
+          {1, 5},
+          {7, 3},
+          {3, 5}
+        };
+    assertEquals(RichestCustomerWealth.solution1(account), 10);
+  }
+}

src/test/java/com/examplehub/leetcode/easy/RunningSumOf1dArrayTest.java

@@ -0,0 +1,23 @@
+package com.examplehub.leetcode.easy;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+class RunningSumOf1dArrayTest {
+  @Test
+  void testSolution1() {
+    int[] nums = {1, 2, 3, 4};
+    RunningSumOf1dArray.solution1(nums);
+    assertEquals(Arrays.toString(nums), Arrays.toString(new int[] {1, 3, 6, 10}));
+
+    nums = new int[] {1, 1, 1, 1, 1};
+    RunningSumOf1dArray.solution1(nums);
+    assertEquals(Arrays.toString(nums), Arrays.toString(new int[] {1, 2, 3, 4, 5}));
+
+    nums = new int[] {3, 1, 2, 10, 1};
+    RunningSumOf1dArray.solution1(nums);
+    assertEquals(Arrays.toString(nums), Arrays.toString(new int[] {3, 4, 6, 16, 17}));
+  }
+}

src/test/java/com/examplehub/leetcode/easy/ShuffleTheArrayTest.java

@@ -0,0 +1,15 @@
+package com.examplehub.leetcode.easy;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Arrays;
+import org.junit.jupiter.api.Test;
+
+class ShuffleTheArrayTest {
+  @Test
+  void testSolution1() {
+    int[] nums = {2, 5, 1, 3, 4, 7};
+    ShuffleTheArray.solution1(nums, 3);
+    assertEquals(Arrays.toString(nums), Arrays.toString(new int[] {2, 3, 5, 4, 1, 7}));
+  }
+}