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  1. #include <algorithm>
  2. #include <iomanip>
  3. #include <iostream>
  4. #include <vector>
  5. #include <set>
  6. #include <numeric>
  7. #include <map>
  8. #include <unordered_map>
  9. using namespace std;
  10. #define all(a) a.begin(), a.end()
  11. #define ll long long
  12. #define fo(i,n) for (long long i = 0; i < n; i++)
  13. #define fastIO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
  14. int main()
  15. {
  16.     fastIO
  17.     ll i,n,m,k,input;
  18.     cin >> i;
  19.     while (i--)
  20.     {
  21.         cin >> n >> m;
  22.         vector<ll> a(n);
  23.         bool cond = true;
  24.         fo(j,n)
  25.         {
  26.             cin >> input;
  27.             a[j] = input;
  28.         }
  29.         cin >> m;
  30.         for (int j = 0; j < n; j++)
  31.         {
  32.             if (j == 0)
  33.             {
  34.                 if (m-a[j] < a[j])
  35.                 {
  36.                     a[j] = m-a[j];
  37.                 }
  38.             }
  39.             else
  40.             {
  41.                 if (m-a[j] <= a[j] && m-a[j] >= a[j-1])
  42.                 {
  43.                     a[j] = m-a[j];
  44.                 }
  45.                 else
  46.                 {
  47.                     if (a[j] < a[j-1])
  48.                     {
  49.                         a[j] = m-a[j];
  50.                     }
  51.                 }
  52.                 if (a[j] < a[j-1])
  53.                 {
  54.                     cond = false;
  55.                     break;
  56.                 }
  57.             }
  58.         }
  59.         if (cond)
  60.         {
  61.             cout << "YES";
  62.         }
  63.         else
  64.         {
  65.             cout << "NO";
  66.         }
  67.         cout << '\n';
  68.     }
  69. }
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin
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5
1 1
5
9
3 1
1 4 3
3
4 1
1 4 2 5
6
4 1
5 4 10 5
4
3 1
9 8 7
8
stdout
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YES
NO
YES
NO
YES
https://ideone.com/4j2xO4
language:
C++14 (gcc 8.3)
created:
12 days ago
visibility:
public

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