URAL 1009 K-based Numbers (DFS)

#include <stdio.h>int numOfDigits, base;int result;void isValid(int digits, int preDigit){if (digits > numOfDigits){result++;return;}int digit;for (digit = 0; digit < base; digit++){if (preDigit == 0 && digit == 0)//剪枝后可以通过continue;isValid(digits + 1, digit);}}int main(){scanf("%d %d", &numOfDigits, &base);isValid(1, 0);printf("%d\n", result);return 0;}