Add kattis prob abc in C

kattis/abc/solution.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int compare (const void * a, const void * b) {
+    return (*(int*)a - *(int*)b);
+}
+
+int main() {
+    int n[3];
+    scanf("%d %d %d", &n[0], &n[1], &n[2]);
+    qsort(n, 3, sizeof(int), compare);
+    char c[5];
+    scanf("%s", c);
+    int i;
+    for (i = 0; i < 3; ++i) {
+        printf("%d ", n[c[i]-'A']);
+    }
+    printf("\n");
+}