code about list

Author: flx413

2-3.删除链表中间结点和a除以b位置的结点.cpp

@@ -0,0 +1,55 @@
+typedef struct Node {
+    int value;
+    Node* next;
+
+    Node( int data ) {
+        this.value = data;
+    }
+} Node;
+
+Node* removeMidNode( Node* head ) {
+    if( head == NULL || head->next == NULL ) {
+        return head;
+    }
+    if( head->next->next == NULL ) {
+        return head->next;
+    }
+
+    Node* pre = head;
+    Node* cur = head->next->next;
+    while( cur->next != NULL && cur->next->next != NULL ) {
+        pre = pre->next;
+        cur = cur->next->next;
+    }
+    Node* mid = pre->next;
+    pre->next = pre->next->next;
+    delete mid;
+    mid = NULL;
+
+    return head;
+}
+
+Node* removeByRatio( Node* head, int a, int b ) {
+    if( a < 1 || a > b ) return head;
+
+    int len = 0;
+    Node* cur = head;
+    while( cur != NULL ) {
+        len++;
+        cur = cur->next;
+    }
+
+    int pos = (int)ceil( ((double)( a * n ) ) / (double)b );
+    if( pos == 1 ) {
+        head = head->next;
+    }
+    else if( pos > 1 ) {
+        cur = head;
+        while( --pos != 1 ) {
+            cur = cur->next;
+        }
+        cur->next = cur->next->next;
+    }
+
+    return head;
+}

2-4.反转单向和双向链表.cpp

@@ -0,0 +1,46 @@
+typedef struct Node {
+    int value;
+    Node* next;
+
+    Node( int data ) {
+        this.value = data;
+    }
+} Node;
+
+Node* reverseList( Node* head ) {
+    Node* pre = NULL;
+    Node* next = NULL;
+    while( head != NULL ) {
+        next = head->next;
+        head->next = pre;
+        pre = head;
+        head = next;
+    }
+
+    return pre;
+}
+
+
+
+typedef struct DoubleNode {
+    int value;
+    DoubleNode* next;
+    DoubleNode* last;
+    DoubleNode( int data ) {
+        this.value = data;
+    }
+} DoubleNode;
+
+DoubleNode* reverseList( DoubleNode* head ) {
+    DoubleNode* pre = NULL;
+    DoubleNode* next = NULL;
+    while( head != NULL ) {
+        next = head->next;
+        head->next = pre;
+        head->last = next;
+        pre = head;
+        head = next;
+    }
+
+    return pre;
+}

2-5.反转部分单链表.cpp

@@ -0,0 +1,38 @@
+typedef struct Node {
+    int value;
+    Node* next;
+
+    Node( int data ) {
+        this.value = data;
+    }
+} Node;
+
+Node* reversePart( Node* head, int from, int to ) {
+    int len = 0;
+    Node* node1 = NULL;
+    Node* fPre = NULL;
+    Node* tPos = NULL;
+    while( node1 != NULL ) {
+        len++;
+        fPre = len == from - 1 ? node1 : fPre;
+        tPos = len == to + 1 ? node1 : tPos;
+        node1 = node1->next;
+    }
+    if( from > to || from < 1 || to > len ) return head;
+
+    node1 = fPre == NULL ? head : fPre.next;
+    Node* node2 = node1->next;
+    node1>next = tPos;
+    Node* next = NULL;
+    while( node2 != tPos ) {
+        next = node2->next;
+        node2->next = node1;
+        node1 = node2;
+        node2 = next;
+    }
+    if( fPre != NULL ) {
+        fPre->next = node1;
+        return head;
+    }
+    return node1;
+}

2-6.环形单链表的约瑟夫环问题.cpp

@@ -0,0 +1,38 @@
+typedef struct Node {
+    int value;
+    Node* next;
+
+    Node( int data ) {
+        this.value = data;
+    }
+} Node;
+
+Node* josephusKill( Node* head, int m ) {
+    if( head == NULL || head->next == head || m < 1 ) return head;
+
+    Node* last = head;
+    while( last->next != head ) {
+        last = last->next;
+    }
+    int count = 0;
+    while( head != last ) {
+        if( ++count == m ) {
+            last->next = head->next;
+            count = 0;
+        }
+        else {
+            last = last->next;
+        }
+        head = last->next;
+    }
+
+    return head;
+}
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