1120. Friend Numbers (20)解题报告

利用哈希表记录朋友号。

#define _CRT_SECURE_NO_WARNINGS#include <cstdio>#include <cstdlib>int friendid(int num);int main(void){int tmp, i, cnt, n, first;bool arr[100] = { false };scanf("%d", &n);for (i = 0; i < n; i++) {scanf("%d", &tmp);arr[friendid(tmp)] = true;}cnt = 0;for (i = 0; i < 100; i++) {if (arr[i]) {first = (cnt ? first : i);cnt++;}}printf("%d\n", cnt);printf("%d", first);for (i = first + 1; i < 100; i++) {if (arr[i]) {printf(" %d", i);}}putchar('\n');return 0;}int friendid(int num){int id = 0;while (num) {id += num % 10;num /= 10;}return id;}