diff --git a/examples/aoc2023/day02/part1.jou b/examples/aoc2023/day02/part1.jou
index 5e44a301..e6ad8ec8 100644
--- a/examples/aoc2023/day02/part1.jou
+++ b/examples/aoc2023/day02/part1.jou
@@ -19,7 +19,7 @@ def game_is_possible(game_data: byte*) -> bool:
 
         n: int
         color: byte[10]
-        assert sscanf(chunk, "%d %10s", &n, color) == 2
+        assert sscanf(chunk, "%d %9s", &n, color) == 2
 
         if strcmp(color, "red") == 0 and n > 12:
             return False
diff --git a/examples/aoc2023/day02/part2.jou b/examples/aoc2023/day02/part2.jou
index 4517320e..37bb5c11 100644
--- a/examples/aoc2023/day02/part2.jou
+++ b/examples/aoc2023/day02/part2.jou
@@ -11,7 +11,7 @@ class Game:
     def update(self, text: byte*) -> void:
         n: int
         color: byte[10]
-        assert sscanf(text, "%d %10s", &n, color) == 2
+        assert sscanf(text, "%d %9s", &n, color) == 2
 
         if strcmp(color, "red") == 0 and n > self->red:
             self->red = n
diff --git a/examples/aoc2023/day07/part1.jou b/examples/aoc2023/day07/part1.jou
new file mode 100644
index 00000000..147b52ec
--- /dev/null
+++ b/examples/aoc2023/day07/part1.jou
@@ -0,0 +1,148 @@
+import "stdlib/io.jou"
+import "stdlib/str.jou"
+
+class Hand:
+    letters: byte[6]
+    bid: int
+
+    def count(self, letter: byte) -> int:
+        n = 0
+        for i = 0; i < 5; i++:
+            if self->letters[i] == letter:
+                n++
+        return n
+
+    def all_same(self) -> bool:
+        return self->count(self->letters[0]) == 5
+
+    def all_but_one_same(self) -> bool:
+        return self->count(self->letters[0]) == 4 or self->count(self->letters[1]) == 4
+
+    def three_same_and_two_same(self) -> bool:
+        # ensure that every count is either 3 or 2
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 3 and n != 2:
+                return False
+        return True
+
+    def three_same_two_distinct(self) -> bool:
+        # ensure that every count is either 3 or 1, and count 3 appears
+        found3 = False
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 3 and n != 1:
+                return False
+            if n == 3:
+                found3 = True
+        return found3
+
+    def two_pairs_one_distinct(self) -> bool:
+        # ensure that every count is either 2 or 1, and count 1 appears only once
+        count1 = 0
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 2 and n != 1:
+                return False
+            if n == 1:
+                count1++
+        return count1 == 1
+
+    def one_pair(self) -> bool:
+        # ensure that every count is either 2 or 1, and exactly 2 cards have count 2
+        count2 = 0
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 2 and n != 1:
+                return False
+            if n == 2:
+                count2++
+        return count2 == 2
+
+    def all_distinct(self) -> bool:
+        for i = 0; i < 5; i++:
+            if self->count(self->letters[i]) != 1:
+                return False
+        return True
+
+    def hand_type_strength(self) -> int:
+        # check that i did this right, exactly one should be true
+        # return index of true in list
+        bools = [
+            self->all_distinct(),
+            self->one_pair(),
+            self->two_pairs_one_distinct(),
+            self->three_same_two_distinct(),
+            self->three_same_and_two_same(),
+            self->all_but_one_same(),
+            self->all_same(),
+        ]
+
+        result = -1
+        for i = 0; i < sizeof(bools)/sizeof(bools[0]); i++:
+            if bools[i]:
+                assert result == -1
+                result = i
+
+        assert result != -1
+        return result
+
+    # Return value:
+    #   +1  if self > other
+    #   0   if self == other
+    #   -1  if self < other
+    def compare(self, other: Hand*) -> int:
+        if self->hand_type_strength() > other->hand_type_strength():
+            return 1
+        if self->hand_type_strength() < other->hand_type_strength():
+            return -1
+
+        for i = 0; i < 5; i++:
+            s = "23456789TJQKA"
+            self_idx_ptr = strchr(s, self->letters[i])
+            other_idx_ptr = strchr(s, other->letters[i])
+            assert self_idx_ptr != NULL and other_idx_ptr != NULL
+            if self_idx_ptr > other_idx_ptr:
+                return 1
+            if self_idx_ptr < other_idx_ptr:
+                return -1
+
+        return 0
+
+
+def swap(h1: Hand*, h2: Hand*) -> void:
+    temp = *h1
+    *h1 = *h2
+    *h2 = temp
+
+
+def sort(hands: Hand*, nhands: int) -> void:
+    # bubble sort go brrr
+    for sorted_part_len = 1; sorted_part_len < nhands; sorted_part_len++:
+        i = sorted_part_len
+        while i > 0 and hands[i-1].compare(&hands[i]) == 1:
+            swap(&hands[i-1], &hands[i])
+            i--
+
+
+def main() -> int:
+    hands: Hand[2000]
+    nhands = 0
+
+    f = fopen("sampleinput.txt", "r")
+    assert f != NULL
+
+    while fscanf(f, "%5s %d\n", &hands[nhands].letters, &hands[nhands].bid) == 2:
+        nhands++
+        assert nhands < sizeof(hands)/sizeof(hands[0])
+
+    fclose(f)
+
+    sort(hands, nhands)
+
+    sum = 0
+    for i = 0; i < nhands; i++:
+        sum += (i+1) * hands[i].bid
+    printf("%d\n", sum)  # Output: 6440
+
+    return 0
diff --git a/examples/aoc2023/day07/part2.jou b/examples/aoc2023/day07/part2.jou
new file mode 100644
index 00000000..7b69eb59
--- /dev/null
+++ b/examples/aoc2023/day07/part2.jou
@@ -0,0 +1,184 @@
+import "stdlib/io.jou"
+import "stdlib/str.jou"
+import "stdlib/mem.jou"
+
+class Hand:
+    letters: byte[6]
+    bid: int
+
+    # optimization to speed up sorting
+    cached_hand_type_strength: int
+
+    def count(self, letter: byte) -> int:
+        n = 0
+        for i = 0; i < 5; i++:
+            if self->letters[i] == letter:
+                n++
+        return n
+
+    def all_same(self) -> bool:
+        return self->count(self->letters[0]) == 5
+
+    def all_but_one_same(self) -> bool:
+        return self->count(self->letters[0]) == 4 or self->count(self->letters[1]) == 4
+
+    def three_same_and_two_same(self) -> bool:
+        # ensure that every count is either 3 or 2
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 3 and n != 2:
+                return False
+        return True
+
+    def three_same_two_distinct(self) -> bool:
+        # ensure that every count is either 3 or 1, and count 3 appears
+        found3 = False
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 3 and n != 1:
+                return False
+            if n == 3:
+                found3 = True
+        return found3
+
+    def two_pairs_one_distinct(self) -> bool:
+        # ensure that every count is either 2 or 1, and count 1 appears only once
+        count1 = 0
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 2 and n != 1:
+                return False
+            if n == 1:
+                count1++
+        return count1 == 1
+
+    def one_pair(self) -> bool:
+        # ensure that every count is either 2 or 1, and exactly 2 cards have count 2
+        count2 = 0
+        for i = 0; i < 5; i++:
+            n = self->count(self->letters[i])
+            if n != 2 and n != 1:
+                return False
+            if n == 2:
+                count2++
+        return count2 == 2
+
+    def all_distinct(self) -> bool:
+        for i = 0; i < 5; i++:
+            if self->count(self->letters[i]) != 1:
+                return False
+        return True
+
+    def hand_type_strength_without_J_special_casing(self) -> int:
+        # check that i did this right, exactly one should be true
+        # return index of true in list
+        bools = [
+            self->all_distinct(),
+            self->one_pair(),
+            self->two_pairs_one_distinct(),
+            self->three_same_two_distinct(),
+            self->three_same_and_two_same(),
+            self->all_but_one_same(),
+            self->all_same(),
+        ]
+
+        result = -1
+        for i = 0; i < sizeof(bools)/sizeof(bools[0]); i++:
+            if bools[i]:
+                assert result == -1
+                result = i
+
+        assert result != -1
+        return result
+
+    def hand_type_strength(self) -> int:
+        if self->cached_hand_type_strength != -1:
+            return self->cached_hand_type_strength
+
+        variations: Hand* = malloc(sizeof(variations[0]))
+        variations[0] = *self
+        nvariations = 1
+
+        for i = 0; i < 5; i++:
+            if self->letters[i] == 'J':
+                # Duplicate each existing variation 13 times
+                nvariations *= 13
+                variations = realloc(variations, sizeof(variations)[0] * nvariations)
+                for isrc = nvariations/13 - 1; isrc >= 0; isrc--:
+                    for idest = 13*isrc; idest < 13*(isrc+1); idest++:
+                        variations[idest] = variations[isrc]
+
+                # Replace i'th letter in every possible way
+                for k = 0; k < nvariations; k++:
+                    variations[k].letters[i] = "J23456789TQKA"[k % 13]
+
+        best = -1
+        for i = 0; i < nvariations; i++:
+            value = variations[i].hand_type_strength_without_J_special_casing()
+            if value > best:
+                best = value
+
+        free(variations)
+        self->cached_hand_type_strength = best
+        return best
+
+    # Return value:
+    #   +1  if self > other
+    #   0   if self == other
+    #   -1  if self < other
+    def compare(self, other: Hand*) -> int:
+        if self->hand_type_strength() > other->hand_type_strength():
+            return 1
+        if self->hand_type_strength() < other->hand_type_strength():
+            return -1
+
+        for i = 0; i < 5; i++:
+            s = "J23456789TQKA"
+            self_idx_ptr = strchr(s, self->letters[i])
+            other_idx_ptr = strchr(s, other->letters[i])
+            assert self_idx_ptr != NULL and other_idx_ptr != NULL
+            if self_idx_ptr > other_idx_ptr:
+                return 1
+            if self_idx_ptr < other_idx_ptr:
+                return -1
+
+        return 0
+
+
+def swap(h1: Hand*, h2: Hand*) -> void:
+    temp = *h1
+    *h1 = *h2
+    *h2 = temp
+
+
+def sort(hands: Hand*, nhands: int) -> void:
+    # bubble sort go brrr
+    for sorted_part_len = 1; sorted_part_len < nhands; sorted_part_len++:
+        i = sorted_part_len
+        while i > 0 and hands[i-1].compare(&hands[i]) == 1:
+            swap(&hands[i-1], &hands[i])
+            i--
+
+
+def main() -> int:
+    hands: Hand[2000]
+    nhands = 0
+
+    f = fopen("sampleinput.txt", "r")
+    assert f != NULL
+
+    while fscanf(f, "%5s %d\n", &hands[nhands].letters, &hands[nhands].bid) == 2:
+        hands[nhands].cached_hand_type_strength = -1
+        nhands++
+        assert nhands < sizeof(hands)/sizeof(hands[0])
+
+    fclose(f)
+
+    sort(hands, nhands)
+
+    sum = 0
+    for i = 0; i < nhands; i++:
+        sum += (i+1) * hands[i].bid
+    printf("%d\n", sum)  # Output: 5905
+
+    return 0
diff --git a/examples/aoc2023/day07/sampleinput.txt b/examples/aoc2023/day07/sampleinput.txt
new file mode 100644
index 00000000..e3500c3b
--- /dev/null
+++ b/examples/aoc2023/day07/sampleinput.txt
@@ -0,0 +1,5 @@
+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483
diff --git a/valgrind-suppressions.sup b/valgrind-suppressions.sup
index 4ca6162c..e189cd5e 100644
--- a/valgrind-suppressions.sup
+++ b/valgrind-suppressions.sup
@@ -20,7 +20,7 @@
 {
    <llvm functions>
    Memcheck:Leak
-   match-leak-kinds: reachable
+   match-leak-kinds: reachable,possible
    ...
    obj:*/libLLVM*.so.*
    ...