try to solve 3 kyu

Author: clingoram

javascript/index.js

@@ -2,6 +2,7 @@
 import { format } from 'node:path';
 import {ExecutionTimer} from './time.js';
 import assert from 'node:assert/strict';
+import { count } from 'node:console';
 
 /*
 22. Generate Parentheses
@@ -1169,20 +1170,57 @@ var specialTriplets = function(nums) {
  */
 function smaller(arr) {
   // 這方法ok，但不適用於large test cases
-  let ans = [];
-  for(let i = 0;i < arr.length;++i) {
+  // let ans = [];
+  // for(let i = 0;i < arr.length;++i) {
+  //   let count = 0;
+  //   for(let j = 0;j < arr.length;j++) {
+  //     // if(arr[i] === arr[j]){
+  //     //   continue;
+  //     // }
+  //     if(arr[i] > arr[j]){
+  //       count++;
+  //     }
+  //    }
+  //    ans[i] = count;
+  // }
+  // return ans;
+
+  return arr.map((current, i) => {
     let count = 0;
-    for(let j = i + 1;j < arr.length;j++) {
-      if(arr[i] === arr[j]){
-        continue;
-      }
-      if(arr[i] > arr[j]){
-        count++;
-      }
-     }
-     ans[i] = count;
-  }
-  return ans;
+    // 比較當前元素右邊所有的元素
+    for (let j = 0; j < arr.length; j++) {
+        if (arr[j] < current) {
+            count++;
+        }
+    }
+    return count;
+  });
+
+  // binary search
+  // const result = new Array(arr.length).fill(0);
+  //   const sortedArray = [];
+
+  //   // 從右往左處理每個元素
+  //   for (let i = arr.length - 1; i >= 0; i--) {
+  //       const current = arr[i];
+      
+  //       // binary search
+  //       let left = 0;
+  //       let right = sortedArray.length;
+
+  //       while (left < right) {
+  //           const mid = Math.floor((left + right) / 2);
+  //           if (sortedArray[mid] < current) {
+  //               left = mid + 1;
+  //           } else {
+  //               right = mid;
+  //           }
+  //       }
+  //       result[i] = left;
+
+  //       sortedArray.splice(left, 0, current);
+  //   }
+  //   return result;
 }
 console.log(assert.deepEqual(smaller([5, 4, 7, 9, 2, 4, 1, 4, 5, 6]), [5, 2, 6, 6, 1, 1, 0, 0, 0, 0]));
 console.log(assert.deepEqual(smaller([5, 4, 3, 2, 1]), [4, 3, 2, 1, 0]))