feat(1721): 遍历链表

descire · descire · commit 8e3b005bd8f5 · 2022-03-16T23:56:29.000+08:00
diff --git a/Linked-List/1721/solution1.js b/Linked-List/1721/solution1.js
@@ -0,0 +1,43 @@
+/**
+ * 时间复杂度：O(n)
+ * 空间复杂度：O(1)
+ */
+const swapNodes = function(head, k) {
+    let length = 0;
+
+    let x = null;
+    let xPreHead = null;
+
+    let currentHead = head;
+    while (currentHead) {
+        length++;
+        if (length === k - 1) {
+            xPreHead = currentHead;
+        }
+        if (length === k) {
+            x = currentHead;
+        }
+        currentHead = currentHead.next;
+    }
+
+    const xSufHead = x.next;
+
+    let k2 = length - k;
+    let y = null;
+    let yPreHead = null;
+    currentHead = head;
+    while (k2--) {
+        yPreHead = currentHead;
+        currentHead = currentHead.next;
+    }
+    y = currentHead;
+    const ySufHead = y.next;
+
+    const xval = x.val;
+    const yval = y.val;
+
+    x.val = yval;
+    y.val = xval;
+
+    return head;
+};
