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Beauty of Array ZOJ - 3872(思維題)

 

Edward has an array A with N integers. He defines the beauty of an array as the summation of all distinct integers in the array. Now Edward wants to know the summation of the beauty of all contiguous subarray of the array A.

Input

There are multiple test cases. The first line of input contains an integer T

indicating the number of test cases. For each test case:

The first line contains an integer N (1 <= N <= 100000), which indicates the size of the array. The next line contains N positive integers separated by spaces. Every integer is no larger than 1000000.

Output

For each case, print the answer in one line.

Sample Input

3
5
1 2 3 4 5
3
2 3 3
4
2 3 3 2

Sample Output

105
21
38


題意就是給你一個數組,讓你求1~1,1~2,1~3,1~4.... 1~n,
               2~2,2~3, 2~4.... 2~n
                 ....................
                      n-1~n-1 n-1~n
                           n~n
這些區間內不同數字的和,然後求總和。

思路:就是從右往左遍歷,找某個數右邊第一次出現這個數的位置,如果是第一次出現那麼這個位置就是n
然後加加乘乘就行了


程式碼如下:
 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 using namespace std;
 5 const int N=1e6+10;
 6 const int NN=1e5+100;
 7 int pos[N],a[NN];
 8 int main()
 9 {
10     int t;
11     int n;
12     scanf("%d",&t);
13     long long ans,tans;
14     while(t--)
15     {
16         scanf("%d",&n);
17         for(int i=0;i<n;i++)
18         {
19             scanf("%d",&a[i]);
20             pos[a[i]]=-1;//標記每個數都沒出現過
21         }
22         ans=0,tans=0;
23         for(int i=n-1;i>=0;i--)
24         {
25             if(pos[a[i]]==-1)
26                 tans+=a[i]*(n-i);
27             else
28                 tans+=a[i]*(pos[a[i]]-i);
29             pos[a[i]]=i;
30             ans+=tans;
31         }
32         printf("%lld\n",ans);
33     } 
34     return 0;
35 }