第11课。

11/Optional01.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+
+void calcNext(int lastResult) {
+    if (lastResult == 6174)
+    {
+        return;
+    }
+}
+
+int main() {
+    int digits[10] = {0};
+    int maxComb, minComb;
+    int nowChecking;
+    int curDigit = 0;
+    int i = 0, j = 0;
+    scanf("%d", &nowChecking);
+    while (nowChecking > 0) {
+        curDigit = nowChecking % 10;
+        if (digits[curDigit] > 0) {
+            printf("error");
+            return 0;
+        }
+        else {
+            digits[curDigit] = 1;
+            nowChecking /= 10;
+        }
+    }
+    while (nowChecking != 6174) {
+        maxComb = 0;
+        minComb = 0;
+        for (i = 0; i < 10; i++) {
+            for (j = 0; j < digits[i]; j++) {
+                minComb = minComb * 10 + i;
+            }
+        }
+        for (i = 9; i >= 0; i--) {
+            for (j = 0; j < digits[i]; j++) {
+                maxComb = maxComb * 10 + i;
+            }
+        }
+        nowChecking = maxComb - minComb;
+        printf("%d - %d = %d\n", maxComb, minComb, nowChecking);
+        for (i = 0; i < 10; i++) {
+            digits[i] = 0;
+        }
+        while (nowChecking > 0) {
+            digits[nowChecking % 10]++;
+            nowChecking /= 10;
+        }
+        nowChecking = maxComb - minComb;
+    }
+    return 0;
+}