From a8bcc6899ce7362808fd445667af9dd5039c4ea6 Mon Sep 17 00:00:00 2001
From: Jesse Brault <jbrault@mac.com>
Date: Tue, 11 Feb 2025 17:19:23 -0600
Subject: [PATCH] Update to use HashMap with chaining, cli args, and freeing
 all memory (no leaks).

---
 two-sum/Makefile    |   3 ++
 two-sum/runTwoSum.c |  54 ++++++++++++++---------
 two-sum/twoSum.c    | 104 ++++++++++++++++++++++++++++----------------
 3 files changed, 104 insertions(+), 57 deletions(-)

diff --git a/two-sum/Makefile b/two-sum/Makefile
index cf8a1c5..cacf3b0 100644
--- a/two-sum/Makefile
+++ b/two-sum/Makefile
@@ -3,3 +3,6 @@ twoSum: runTwoSum.c twoSum.c
 
 run: twoSum
 	./twoSum
+
+valgrind: twoSum
+	valgrind --leak-check=full ./twoSum -t 3 1 2
\ No newline at end of file
diff --git a/two-sum/runTwoSum.c b/two-sum/runTwoSum.c
index 386bb1f..49a49cc 100644
--- a/two-sum/runTwoSum.c
+++ b/two-sum/runTwoSum.c
@@ -1,26 +1,40 @@
 #include "./twoSum.c"
-#include <stdbool.h>
 #include <stdio.h>
+#include <string.h>
 
-int main() {
-    int nums[] = { 0, 4, 3, 0 };
-    int returnSize = 0;
-    int *result = twoSum(nums, 4, 0, &returnSize);
-    bool foundFirst, foundSecond;
-    for (int i = 0; i < returnSize; i++) {
-        switch (result[i]) {
-        case 0:
-            foundFirst = true;
-            break;
-        case 3:
-            foundSecond = true;
-            break;
-        }
-    }
-    if (foundFirst && foundSecond) {
-        return 0;
-    } else {
-        fprintf(stderr, "Did not find indices [0, 1]\n");
+#define USAGE "Usage: twoSum -t <target> <e0> <e1> [...<es>]\n"
+
+int main(int argc, char *argv[]) {
+    if (argc < 5) {
+        fprintf(stderr, USAGE);
         return 1;
     }
+    if (strcmp("-t", argv[1]) != 0) {
+        fprintf(stderr, USAGE);
+        return 1;
+    }
+    int target = atoi(argv[2]);
+    int *nums = malloc(sizeof(int) * (argc - 3));
+    
+    for (int i = 3; i < argc; i++) {
+        nums[i - 3] = atoi(argv[i]);
+    }
+
+    int returnSize = 0;
+    int *result = twoSum(nums, argc - 3, target, &returnSize);
+
+    if (!returnSize) {
+        fprintf(stderr, "Did not find two indices.");
+        return 1;
+    }
+
+    for (int i = 0; i < returnSize; i++) {
+        printf("%i ", result[i]);
+    }
+    printf("\n");
+
+    free(result);
+    free(nums);
+
+    return 0;
 }
diff --git a/two-sum/twoSum.c b/two-sum/twoSum.c
index ce75c12..e6221b6 100644
--- a/two-sum/twoSum.c
+++ b/two-sum/twoSum.c
@@ -4,15 +4,20 @@ typedef struct {
     int key, value;
 } HashMapEntry;
 
+typedef struct EntryList {
+    HashMapEntry *entry;
+    struct EntryList *next;
+} EntryList;
+
 typedef struct {
     int size;
-    HashMapEntry **entries;
+    EntryList **entries;
 } HashMap;
 
 HashMap *makeHashMap(int size) {
     HashMap *m = malloc(sizeof(HashMap));
     m->size = size;
-    m->entries = malloc(size * sizeof(HashMapEntry*));
+    m->entries = malloc(size * sizeof(EntryList *));
     for (int i = 0; i < size; i++) {
         m->entries[i] = NULL;
     }
@@ -30,48 +35,72 @@ HashMapEntry *makeEntry(int key, int value) {
     return e;
 }
 
-#define PUT_SUCCESS 1
-#define PUT_FAIL 0
-
-int putAt(HashMap *m, HashMapEntry *e, int index) {
-    if (m->entries[index] == NULL) {
-        m->entries[index] = e;
-        return PUT_SUCCESS;
-    }
-    return PUT_FAIL;
+EntryList *makeLinkedList(HashMapEntry *e) {
+    EntryList *l = malloc(sizeof(EntryList));
+    l->entry = e;
+    l->next = NULL;
+    return l;
 }
 
-int put(HashMap *m, int key, int value) {
+void appendEntryList(EntryList *l, HashMapEntry *e) {
+    while (l->next != NULL)
+        l = l->next;
+    l->next = makeLinkedList(e);
+}
+
+void putAt(HashMap *m, HashMapEntry *e, int index) {
+    if (m->entries[index] == NULL) {
+        m->entries[index] = makeLinkedList(e);
+    } else {
+        appendEntryList(m->entries[index], e);
+    }
+}
+
+void put(HashMap *m, int key, int value) {
     int hash = hashCode(m, key);
     HashMapEntry *e = makeEntry(key, value);
-    for (int i = hash; i < m->size; i++) {
-        if (putAt(m, e, i)) return PUT_SUCCESS; 
-    }
-    for (int i = 0; i < hash; i++) {
-        if (putAt(m, e,i)) return PUT_SUCCESS; 
-    }
-    return PUT_FAIL;
+    putAt(m, e, hash);
 }
 
 HashMapEntry *get(HashMap *m, int key) {
     int hash = hashCode(m, key);
-    for (int i = hash; i < m->size; i++) {
-        if (m->entries[i] != NULL) {
-            HashMapEntry *e = m->entries[i];
-            if (e->key == key) {
-                return e;
-            }
-        }
+    EntryList *l = m->entries[hash];
+    while (l != NULL && l->entry->key != key) {
+        l = l->next;
     }
-    for (int i = 0; i < hash; i++) {
-        if (m->entries[i] != NULL) {
-            HashMapEntry *e = m->entries[i];
-            if (e->key == key) {
-                return e;
-            }
-        }
+    if (l == NULL) return NULL;
+    return l->entry;
+}
+
+void freeEntryList(EntryList *l) {
+    int size = 0;
+    EntryList *current = l;
+    while (current != NULL) {
+        current = current->next;
+        size++;
     }
-    return NULL;
+    
+    EntryList **reversed = malloc(size * sizeof(EntryList *));
+    current = l;
+    for (int i = 0; i < size; i++) {
+        reversed[size - i - 1] = current;
+        current = current->next;
+    }
+
+    for (int i = 0; i < size; i++) {
+        free(reversed[i]->entry);
+        free(reversed[i]);
+    }
+
+    free(reversed);
+}
+
+void freeHashMap(HashMap *m) {
+    for (int i = 0; i < m->size; i++) {
+        freeEntryList(m->entries[i]);
+    }
+    free(m->entries);
+    free(m);
 }
 
 /**
@@ -87,12 +116,13 @@ int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
             result[0] = i;
             result[1] = e->value;
             *returnSize = 2;
+            freeHashMap(m);
             return result;
-        } else if (!put(m, nums[i], i)) {
-            *returnSize = 0;
-           return malloc(0); // fail 
+        } else {
+            put(m, nums[i], i);
         }
     }
+    freeHashMap(m);
     *returnSize = 0;
     return malloc(0);
 }
\ No newline at end of file