http://ac.jobdu.com/problem.php?id=1377
首先庆祝昨天晚上没头疼～～～
WA了无数次，找不到错误，两天之后双重写了一遍，一次就神奇的AC了。。
从小往大放，因为，对于最小的数来说，肯定后面要放比它大1的数，依次类推，贪心是可行的。
1 #include <stdio.h>
2 #include <stdlib.h>
3 #define INF 0x7fffffff
4 int N;
5 int num_array[10005];
6 void init()
7 {
8 int i;
9 for(i=0;i<=10000;i++)
10 num_array[i]=0;
11 }
12 int main()
13 {
14 while(scanf("%d",&N)!=EOF){
15 int i;
16 int temp;
17 int num=0;
18 int min_num=INF;
19 init();
20 bool flag=true;
21 for(i=0;i<N;i++){
22 scanf("%d",&temp);
23 if(num_array[temp]==0)
24 num++;
25 num_array[temp]++;
26 if(temp<min_num)
27 min_num=temp;
28 }
29 int cur_num=min_num;
30 if(num%2!=0){
31 printf("NO\n");
32 continue;
33 }
34 if(num==2){
35 if(cur_num+1<=10000&&num_array[cur_num]==num_array[cur_num+1]){
36 printf("YES\n");
37 }else{
38 printf("NO\n");
39 }
40 continue;
41 }
42 if(num==1){
43 printf("NO\n");
44 continue;
45 }
46 cur_num=min_num;
47 for(i=1;i<=num-2;i++){
48 if(cur_num+1<=10000&&num_array[cur_num+1]>num_array[cur_num]){
49 num_array[cur_num+1]-=num_array[cur_num];
50 cur_num++;
51 }else{
52 flag=false;
53 break;
54 }
55 }
56 if(!flag){
57 printf("NO\n");
58 }else if(cur_num+1<=10000&&num_array[cur_num+1]==num_array[cur_num]){
59 printf("YES\n");
60 }else{
61 printf("NO\n");
62 }
63 }
64 }