题目链接:hdu 5568 sequence2
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxn = 105;
struct Bign {
int n,s[maxn<<1];
Bign (int t = 0) { init(); s[0] = t; }
void init () { n = 1; memset(s,0,sizeof(s)); }
void add(const Bign& a) {
int res = 0;
for (int i = 0; i < a.n || i < n; i++) {
if (i < a.n) res += a.s[i];
if (i < n) res += s[i];
s[i] = res % 10;
res /= 10;
}
n = max(a.n,n);
while (res) {
s[n++] = res % 10;
res /= 10;
}
}
}dp[maxn][maxn],ONE(1);
int N,K,A[maxn];
void solve () {
Bign ans(0);
for (int i = 1; i <= N; i++) {
for (int j = 1; j <= K; j++)
dp[i][j].init();
}
for (int i = 1; i <= N; i++) {
dp[i][1].add(ONE);
ans.add(dp[i][K]);
for (int j = i + 1; j <= N; j++) if (A[i] < A[j]) {
for (int k = 2; k <= K; k++) dp[j][k].add(dp[i][k-1]);
}
}
for (int i = ans.n-1; i >= 0; i--) printf("%d",ans.s[i]);
printf("\n");
}
int main () {
while (scanf("%d%d",&N,&K) == 2) {
for (int i = 1; i <= N; i++) scanf("%d",&A[i]);
solve();
}
return 0;
}