-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathT109.java
More file actions
34 lines (29 loc) · 891 Bytes
/
T109.java
File metadata and controls
34 lines (29 loc) · 891 Bytes
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
/**
* @Author:Aliyang
* @Data: Created in 下午4:06 18-6-14
* first-missing-positive：我的解法
* 思路：将1-n之间的正数放到正确的位置，然后遍历看哪个位置下标加1和值不相等
**/
public class T109 {
public int firstMissingPositive(int[] A) {
if (A.length==0)
return 1;
for (int i=0;i<A.length;i++){
while (A[i]>=1&&A[i]<=A.length&&A[A[i]-1]!=A[i]){//将正数n放到位置n-1上
int tmp=A[i];
A[i]=A[A[i]-1];
A[tmp-1]=tmp;
}
}
for (int i=0;i<A.length;i++){
if (i+1!=A[i])
return i+1;
}
return A.length+1;
}
public static void main(String[] args){
T109 t=new T109();
int[] A=new int[]{3,4,-1,1};
System.out.println(t.firstMissingPositive(A));
}
}