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  1. // ~~ icebear love attttttt ~~
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4.  
  5. typedef long long ll;
  6. typedef pair<int, int> ii;
  7. typedef pair<int, ii> iii;
  8.  
  9. template<class T>
  10.     bool minimize(T &a, const T &b) {
  11.         if (a > b) return a = b, true;
  12.         return false;
  13.     }
  14.  
  15. template<class T>
  16.     bool maximize(T &a, const T &b) {
  17.         if (a < b) return a = b, true;
  18.         return false;
  19.     }
  20.  
  21. #define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
  22. #define FORR(i,a,b) for(int i=(a); i>=(b); --i)
  23. #define REP(i, n) for(int i=0; i<(n); ++i)
  24. #define RED(i, n) for(int i=(n)-1; i>=0; --i)
  25. #define MASK(i) (1LL << (i))
  26. #define mp make_pair
  27. #define pb push_back
  28. #define fi first
  29. #define se second
  30. #define all(x) x.begin(), x.end()
  31. #define task "icebearat"
  32.  
  33. const int MOD = 1e9 + 7;
  34. const int inf = 1e9 + 27092008;
  35. const ll INF = 1e18 + 27092008;
  36. const int N = 1e6 + 5;
  37. int n, m;
  38. ii a[N];
  39. ll suff[N];
  40.  
  41. void init(void) {
  42.     cin >> n >> m;
  43.     FOR(i, 1, m) cin >> a[i].fi >> a[i].se;
  44. }
  45.  
  46. void process(void) {
  47.     sort(a + 1, a + m + 1);
  48.     FORR(i, m, 1) suff[i] = suff[i + 1] + a[i].fi;
  49.  
  50.     ll ans = 0;
  51.     FOR(i, 1, m) {
  52.         int p = upper_bound(a + 1, a + m + 1, mp(a[i].se, -inf)) - a;
  53.         int left = n - (m - p + 1);
  54.         if (left <= 0) maximize(ans, suff[m - n + 1]);
  55.         else {
  56.             ll sum = suff[p];
  57.             if (a[i].fi > a[i].se) sum += 1ll * left * a[i].se;
  58.             else sum += a[i].fi + 1ll * (left - 1) * a[i].se;
  59.             maximize(ans, sum);
  60.         }
  61.     }
  62.     cout << ans;
  63. }
  64.  
  65. int main() {
  66.     ios_base::sync_with_stdio(0);
  67.     cin.tie(0); cout.tie(0);
  68.     if (fopen(task".inp", "r")) {
  69.         freopen(task".inp", "r", stdin);
  70.         freopen(task".out", "w", stdout);
  71.     }
  72.     int tc = 1;
  73. //    cin >> tc;
  74.     while(tc--) {
  75.         init();
  76.         process();
  77.     }
  78.     return 0;
  79. }
  80.  
Success #stdin #stdout 0.01s 5284KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/dCqQ6i
language:
C++14 (gcc 8.3)
created:
5 hours ago
visibility:
public

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