Partition list

Signed-off-by: begeekmyfriend <[email protected]>

086_partition_list/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test partition_list.c

086_partition_list/partition_list.c

@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+struct ListNode {
+    int val;
+    struct ListNode *next;
+};
+
+struct ListNode* partition(struct ListNode* head, int x) {
+    struct ListNode dummy;
+    struct ListNode *p = NULL, *start = &dummy, *pivot;    
+    dummy.next = head;
+    for (pivot = head; pivot != NULL; pivot = pivot->next) {
+        if (pivot->val >= x) {
+            break;
+        }
+        start = pivot;
+    }
+
+    struct ListNode *prev;
+    for (p = pivot; p != NULL; p = p->next) {
+        if (p->val < x) {
+            prev->next = p->next;
+            p->next = start->next;
+            start->next = p;
+            start = p;
+            p = prev;
+        }
+        prev = p;
+    }
+    return dummy.next;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test target n1 n2 n3...\n");
+        exit(-1);
+    }
+
+    int i, target = atoi(argv[1]);
+    struct ListNode *head = NULL;
+    struct ListNode *prev = NULL;
+    struct ListNode *p;
+    for (i = 0; i < argc - 2; i++) {
+        p = malloc(sizeof(*p));
+        p->val = atoi(argv[i + 2]);
+        p->next = NULL;
+        if (head == NULL) {
+            head = p;
+            prev = head;
+        } else {
+            prev->next = p;
+            prev = p;
+        }
+    }
+    p = partition(head, target);
+    while (p != NULL) {
+        printf("%d ", p->val);
+        p = p->next;
+    }
+    printf("\n");
+    return 0;
+}