Update README_EN.md

Author: yanglbme

solution/1000-1099/1051.Height Checker/README_EN.md

@@ -142,13 +142,7 @@ func heightChecker(heights []int) int {
 ```ts
 function heightChecker(heights: number[]): number {
     const expected = [...heights].sort((a, b) => a - b);
-    let ans = 0;
-
-    for (let i = 0; i < heights.length; i++) {
-        if (expected[i] !== heights[i]) ans++;
-    }
-
-    return ans;
+    return heights.reduce((acc, cur, i) => acc + (cur !== expected[i] ? 1 : 0), 0);
 }
 ```