找出数组中从未出现的最小正整数java实现

Posted 2020-08-13

 1 /**
 2      * 找出未出现的最小正整数
 3      * @param A
 4      * @param n
 5      * @date 2016-10-7
 6      * @author shaobn
 7      */
 8     public static int findArrayMex(int[] a,int n){
 9         int count = n;
10         int temp = 0;
11         int dir = 1;
12         int num = 0;
13         for(int i = 0;i<count-1;i++){
14             if(a[i]>a[i+1]){
15                 temp = a[i];
16                 a[i]= a[i+1];
17                 a[i+1] = temp;        
18             }
19             if(i==count-2){
20                 count--;
21                 i=-1;
22             }
23         }
24         if(a[0]>1 || a[n-1]<1){
25             return 1;
26         }else {
27             for(int i =0;i<n-1;i++){
28                 if(a[i]>0){
29                     num = i;
30                     break;
31                 }                
32             }
33             if(a[num]>1){
34                 return 1;
35             }else if(a[num]==1) {
36                 for(int i =num+1;i<n-1;i++){
37                     if(a[i]-a[num]>dir){
38                         return a[num]+dir;
39                     }else {
40                         dir++;
41                     }
42                 }
43             }
44         }
45         return a[num]+dir;
46     }