solved: 3 Sum Closest

Author: lambiengcode

README.md

@@ -24,6 +24,7 @@
   - [Valid number](#valid-number)
   - [Text Justification](#text-justification)
   - [3 Sum](#3-sum)
+  - [3 Sum Closest](#3-sum-closest)
 
 ### String to Int - Atoi
 
@@ -639,4 +640,40 @@ List<List<int>> threeSum(List<int> nums) {
 
   return result;
 }
+```
+
+### 3 Sum Closest
+
+```dart
+int threeSumClosest(List<int> nums, int target) {
+  int result = -1;
+  int diff = -1;
+
+  for (int i = 0; i < nums.length - 2; i++) {
+    int left = i + 1;
+    int right = nums.length - 1;
+
+    while (left < right) {
+      final int sum = nums[i] + nums[left] + nums[right];
+
+      if (diff < 0 || (sum - target).abs() < diff) {
+        diff = (sum - target).abs();
+        result = sum;
+      }
+
+      if (diff == 0) {
+        return result;
+      }
+
+      if (right == left + 1) {
+        left++;
+        right = nums.length - 1;
+      } else {
+        right--;
+      }
+    }
+  }
+
+  return result;
+}
 ```

src/3_sum_closest.dart

@@ -0,0 +1,173 @@
+import '../helpers/stop_watch.dart';
+
+void main(List<String> args) {
+  List<List> cases = [
+    // [
+    //   [-1, 2, 1, -4],
+    //   1
+    // ],
+    // [
+    //   [0, 0, 0],
+    //   1
+    // ],
+    // [
+    //   [1, 1, 1, 0],
+    //   100
+    // ],
+    [
+      [
+        40,
+        -53,
+        36,
+        89,
+        -38,
+        -51,
+        80,
+        11,
+        -10,
+        76,
+        -30,
+        46,
+        -39,
+        -15,
+        4,
+        72,
+        83,
+        -25,
+        33,
+        -69,
+        -73,
+        -100,
+        -23,
+        -37,
+        -13,
+        -62,
+        -26,
+        -54,
+        36,
+        -84,
+        -65,
+        -51,
+        11,
+        98,
+        -21,
+        49,
+        51,
+        78,
+        -58,
+        -40,
+        95,
+        -81,
+        41,
+        -17,
+        -70,
+        83,
+        -88,
+        -14,
+        -75,
+        -10,
+        -44,
+        -21,
+        6,
+        68,
+        -81,
+        -1,
+        41,
+        -61,
+        -82,
+        -24,
+        45,
+        19,
+        6,
+        -98,
+        11,
+        9,
+        -66,
+        50,
+        -97,
+        -2,
+        58,
+        17,
+        51,
+        -13,
+        88,
+        -16,
+        -77,
+        31,
+        35,
+        98,
+        -2,
+        0,
+        -70,
+        6,
+        -34,
+        -8,
+        78,
+        22,
+        -1,
+        -93,
+        -39,
+        -88,
+        -77,
+        -65,
+        80,
+        91,
+        35,
+        -15,
+        7,
+        -37,
+        -96,
+        65,
+        3,
+        33,
+        -22,
+        60,
+        1,
+        76,
+        -32,
+        22
+      ],
+      292
+    ]
+  ];
+
+  for (final testcase in cases) {
+    Duration timeWasted = stopwatch(() {
+      print(threeSumClosest(testcase.first, testcase.last));
+    });
+
+    print("Spent: ${timeWasted.inMilliseconds}ms");
+  }
+}
+
+int threeSumClosest(List<int> nums, int target) {
+  int result = -1;
+  int diff = -1;
+
+  for (int i = 0; i < nums.length - 2; i++) {
+    int left = i + 1;
+    int right = nums.length - 1;
+
+    while (left < right) {
+      final int sum = nums[i] + nums[left] + nums[right];
+
+      if (diff < 0 || (sum - target).abs() < diff) {
+        diff = (sum - target).abs();
+        result = sum;
+      }
+
+      if (diff == 0) {
+        return result;
+      }
+
+      if (right == left + 1) {
+        left++;
+        right = nums.length - 1;
+      } else {
+        right--;
+      }
+    }
+  }
+
+  return result;
+}