1 files changed, 73 insertions, 0 deletions
diff --git a/c/0067/main.c b/c/0067/main.c
new file mode 100644
index 0000000..900c685
--- /dev/null
+++ b/c/0067/main.c
@@ -0,0 +1,73 @@
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+    int len;
+    char *buf;
+    int capacity;
+} String;
+
+void String_push(String *self, char c) {
+    if (self->len + 2 >= self->capacity) {
+        int new_capacity = self->capacity * 2;
+        self->buf = realloc(self->buf, new_capacity);
+        self->capacity = new_capacity;
+    }
+    self->buf[self->len] = c;
+    self->buf[self->len + 1] = '\0';
+    self->len++;
+}
+
+void String_init(String *self) {
+    self->capacity = 16;
+    self->buf = malloc(16);
+    self->len = 0;
+    self->buf[0] = '\0';
+}
+
+char* str_reverse(char *s) {
+    int lp = 0, rp = strlen(s) - 1;
+    s = strdup(s);
+    while (lp <= rp) {
+        char tmp = s[lp];
+        s[lp] = s[rp];
+        s[rp] = tmp;
+        rp--;
+        lp++;
+    }
+    return s;
+}
+
+char* addBinary(char* a, char* b) {
+    a = str_reverse(a);
+    b = str_reverse(b);
+    String ret;
+    String_init(&ret);
+    int len_a = strlen(a);
+    int len_b = strlen(b);
+    int len = len_a > len_b ? len_a : len_b;
+    int carry = 0;
+    for (int i = 0; i < len; i++) {
+        char ca, cb;
+        if (i >= len_a) {
+            ca = 0;
+        } else {
+            ca = a[i] - '0';
+        }
+        if (i >= len_b) {
+            cb = 0;
+        } else {
+            cb = b[i] - '0';
+        }
+        char val = ca + cb + carry;
+        String_push(&ret, val % 2 + '0');
+        carry = val / 2;
+    }
+    if (carry) String_push(&ret, '1');
+    free(a);
+    free(b);
+    char *oldbuf = ret.buf;
+    ret.buf = str_reverse(ret.buf);
+    free(oldbuf);
+    return ret.buf;
+}