#include <stdio.h> #include <stdlib.h> #define MAX_QUEUE_SIZE 1000000 // 队列最大容量，适应n=1e6的需求 int main() { int n; scanf("%d", &n); // 初始化队列，存储守序数 long long* queue = (long long*)malloc(MAX_QUEUE_SIZE * sizeof(long long)); int front = 0, rear = 0; // 1-9是初始守序数（一位数） for (int i = 1; i <= 9; i++) { queue[rear++] = i; } long long result = 0; for (int count = 0; count < n; count++) { long long current = queue[front++]; // 取出队首元素 result = current; int last_digit = current % 10; // 可能的下一位数字：last_digit-1, last_digit, last_digit+1（需在0-9范围内） for (int d = last_digit - 1; d <= last_digit + 1; d++) { if (d >= 0 && d <= 9) { long long next_num = current * 10 + d; // 生成新的守序数 queue[rear++] = next_num; } } } printf("%lld\n", result); free(queue); return 0; }