Codeforces Round 314 Div.2

This game is played with trumpet, so now the trumpet is higher than the large rating ... QwQ

A and B are very simple and not much to say.

C: The number of equal-ratio sequences with a length of 3 in the statistical subsequence and K K for the male ratio.

The number of sequences that meet the conditional length of three-to-three are counted from the back-to-forward process.
F (i,j) =∑f (i−1,t) |t=j∗k f (i,j) = \sum f (i-1,t) | t = j*k, when implemented discretization is good ~

However, at that time only judged the A[i]*k<=a[max], and did not judge A[i]*k>=a[min] (k may be negative), so fst ...

 const int MAXN = 2e5 + 5, size = maxn*3;
int N, K, A[MAXN];
Long long ans;
int CNT[MAXN], p[maxn], pl;


Long Long F[MAXN], G[MAXN];
    int main () {#ifndef Online_judge freopen ("c.in", "R", stdin);
Freopen ("C.out", "w", stdout);

    #endif read (n), read (k);

    for (int i = 1; I <= n; i++) read (A[i]), p[i] = a[i];
    Std::sort (p + 1, p + n + 1);

    PL = Std::unique (p + 1, p + N + 1)-(p + 1);

        for (int i = n; i > 0; i--) {int t = Std::lower_bound (p + 1, p + PL + 1, a[i])-p;  if (long long) a[i]*k <= P[PL] && (Long long) a[i]*k >= p[1]) {int v = std::lower_bound (P
            + 1, p + PL + 1, a[i]*k)-p;
        if (A[i]*k = = P[v]) g[t] + = F[v], f[t] + = Cnt[v];
    } cnt[t]++;

    } for (int i = 1; I <= pl; i++) ans + = g[i];

Write (ANS);
    #ifndef Online_judge fclose (stdin);
Fclose (stdout);
#endif return 0; }

D: Reverse processing from the end state, using and checking the set to maintain the longest interval, until the number of >= to meet the actual number of ships to get the answer.

const int MAXN = 2e5 + 5, maxk = MAXN;

int N, K, A, m;
int x[maxk], CNT;
BOOL E[MAXN];

int FA[MAXN], SIZE[MAXN];
int find (int x) {return (x = = Fa[x])? x: (Fa[x] = find (fa[x]));

    } void gather (int x,int y) {if (x > Y) std::swap (x, y);
    x = Find (x), y = Find (y), fa[y] = x;
if (x! = y) size[x] + = Size[y], size[y] = 0;
    } void Init () {read (n), read (k), read (a), read (m);
for (int i = 1; I <= m; i++) read (X[i]), e[x[i]] = true;

    } void Prework () {for (int i = 1; I <= n; i++) Fa[i] = i, size[i] = 1;

    for (int i = 1; I <= n; i++) if (i > 1 &&!e[i] &&!e[i-1]) gather (I, i-1);       
for (int i = 1; I <= n; i++) if (fa[i] = = i &&!e[i]) cnt + = (size[i]+1)/(a+1);

    } int Solve () {if (CNT >= k) return-1; for (int i = m; I >= 1; i--) {if (X[i] > 1 &&!e[x[i]-1]) {cnt-= (size[find (x[i]-1)]
            +1)/(a+1); Gather (X[i]-1, x[I]);
            } if (X[i] < n &&!e[x[i]+1]) {cnt-= (Size[find (x[i]+1)]+1)/(a+1);
        Gather (X[i], x[i] + 1);

        } cnt + = (Size[find (x[i])]+1)/(a+1);

        E[x[i]] = false;
    if (CNT >= k) return i;
} return 0;
    } int main () {#ifndef Online_judge freopen ("d.in", "R", stdin);
Freopen ("D.out", "w", stdout);

    #endif init (), prework ();

Write (Solve ());
    #ifndef Online_judge fclose (stdin);
Fclose (stdout);
#endif return 0; }