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https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
40 lines
1000 B
C++
40 lines
1000 B
C++
#include<cstdio>
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#include<cstdlib>
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#include<cstring>
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#include<iostream>
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#include<algorithm>
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#include<vector>
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using namespace std;
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typedef long long LL;
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const LL mod = 1000000007;
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const int maxn = 100005;
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int b[maxn],a[maxn];
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int n,m;
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LL cnt[maxn];
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LL B[maxn];
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int main() {
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int t;
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cin >> t;
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B[0] = 1;
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for (int i = 1;i < maxn;i++) B[i] = (B[i - 1] * 2) % mod;
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while (t--) {
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memset(cnt, 0, sizeof(cnt));
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cin >> n;
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for (int i = 0;i < n;i++) {
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scanf("%d", &a[i]);
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b[i] = a[i];
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}
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sort(b, b + n);
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m = unique(b, b + n) - b;
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LL ret = 0;
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for (int i = 0;i < n;i++) {
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int x = lower_bound(b, b + m, a[i]) - b;
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ret = ((ret - ((cnt[x] * (LL)a[i]) % mod * B[n - i - 1])%mod)%mod+mod)%mod;
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ret = (ret + B[n - 1] * (LL)a[i]) % mod;
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cnt[x] = (cnt[x] + B[i])%mod;
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}
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cout << ret << endl;
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}
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return 0;
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}
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