Traveling 时间限制: 1 Sec 内存限制: 32 MB 提交: 41 解决: 23 [提交][状态][讨论版] 题目描述 SH likes traveling around the world. When he arrives at a city, he will ask the staff about the number of cities that connected with this city directly. After traveling around a mainland, SH will collate data and judge whether the data is correct. A group of data is correct when it can constitute an undirected graph. 输入 There are multiple test cases. The first line of each test case is a positive integer N (1<=N<=10000) standing for the number of cities in a mainland. The second line has N positive integers a1, a2, …,an. ai stands for the number of cities that connected directly with the ith city. Input will be ended by the END OF FILE. 输出 If a group of data is correct, output “YES” in one line, otherwise, output “NO”. 样例输入 8 7 7 4 3 3 3 2 1 10 5 4 3 3 2 2 2 1 1 1 样例输出 NO YES
;const int MAXN =10010;int p[MAXN];int n;int solve (){for(int i=0;i<n;i++){for(int j=i+1;j<n;j++){if (p[i]>0 && p[j] >0){p[i]– ;p[j]–;}}if (p[i]!=0){return 0;}}return 1;}int main(){while (scanf(“%d”,&n)!=EOF){for(int i=0;i<n;i++)scanf(“%d”,&p[i]);if (solve())printf(“YES\n”);elseprintf(“NO\n”);}return 0;}
，感受最美的风景。你曾经说，
