add a1024

PATAdvanced/1024.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <string.h>
+
+int isPalindromic(char n[])
+{
+    int len = strlen(n);
+    for(int i = 0; i < len / 2; i++)
+        if(n[i] != n[len - i - 1])
+            return 0;
+    return 1;
+}
+
+char* reverse(char n[])
+{
+    char temp;
+    int len = strlen(n);
+    for(int i = 0; i < len / 2; i++)
+    {
+        temp = n[i];
+        n[i] = n[len - i - 1];
+        n[len - i - 1] = temp;
+    }
+    return n;
+}
+
+/* only works when a and b are of the same length */
+void addAtoB(char a[], char b[])
+{
+    int l, s = 0, len = strlen(a);
+
+    for(int i = 0; i < len; i++)
+    {
+        s += (a[i] - '0') + (b[i] - '0');
+        l = s / 10;
+        s %= 10;
+        b[i] = s + '0';
+
+        s = l;
+    }
+
+    if(s)
+        b[len] = s + '0';
+}
+
+int main()
+{
+    int K, steps;
+    char s1[100] = {0}, s2[100] = {0}, *n = s1, *m = s2;
+
+    scanf("%s %d", n, &K);
+    reverse(n);
+
+    for(steps = 0; steps < K && !isPalindromic(n); steps++)
+    {
+        /* change 'm' into reverse of 'n' */
+        strncpy(m, n, 100);
+        reverse(m);
+        /* add n and reversed n, and keep the result in n */
+        addAtoB(m, n);
+    }
+
+    printf("%s\n%d", reverse(n), steps);
+
+    return 0;
+}